From: csagan5 <32685696+csagan5@users.noreply.github.com>
Date: Sat, 14 Sep 2019 10:20:08 +0200
Subject: Bromite subresource adblocker

Add option to configure the ad blocker filters URL
Disable look-alike, metrics, ablation and navigation throttles
Do not use experiments to enable/disable presets
Always enable ad filtering
Download filters by checking Last-Modified header first
Fix RestoreForeignSessionTab by recreating the tab (issue #681)
Enable AutomaticLazyFrameLoadingToAds and AutomaticLazyFrameLoadingToEmbeds features

License: GPL-3.0-only - https://spdx.org/licenses/GPL-3.0-only.html
Change-Id: I09c0504269c659e0f125dfa982148b705cd6528b
---
 chrome/android/BUILD.gn                       |   1 +
 chrome/android/chrome_java_resources.gni      |   2 +
 chrome/android/chrome_java_sources.gni        |   2 +
 .../java/res/layout/adblock_editor.xml        |  67 +++++
 chrome/android/java/res/values/styles.xml     |  18 ++
 chrome/android/java/res/values/values.xml     |   2 +
 .../java/res/xml/adblock_preferences.xml      |  25 ++
 .../android/java/res/xml/main_preferences.xml |   5 +
 .../browser/settings/AdBlockEditor.java       |  91 ++++++
 .../browser/settings/AdBlockPreferences.java  |  61 ++++
 .../chrome/browser/tabmodel/TabModelImpl.java |   2 +-
 chrome/app/generated_resources.grd            |  10 +
 chrome/browser/after_startup_task_utils.cc    |   4 +
 chrome/browser/browser_process.h              |   6 +
 chrome/browser/browser_process_impl.cc        |  20 ++
 chrome/browser/browser_process_impl.h         |   2 +
 chrome/browser/chrome_browser_main.cc         |   3 +
 .../flags/android/cached_feature_flags.cc     |  11 +
 .../browser/flags/CachedFeatureFlags.java     |  10 +
 .../net/system_network_context_manager.cc     |   4 +
 .../sessions/session_restore_android.cc       |   4 +-
 .../strings/android_chrome_strings.grd        |  14 +
 chrome/common/pref_names.cc                   |   3 +
 chrome/common/pref_names.h                    |   1 +
 .../strings/android/site_settings.grdp        |   4 +-
 components/component_updater/BUILD.gn         |   7 +
 .../adblock_updater_service.cc                | 268 ++++++++++++++++++
 .../adblock_updater_service.h                 |  98 +++++++
 .../download_filters_task.cc                  | 222 +++++++++++++++
 .../component_updater/download_filters_task.h | 129 +++++++++
 ...ent_subresource_filter_throttle_manager.cc |  11 +
 .../content/browser/ruleset_service.cc        |  33 ++-
 .../content/browser/ruleset_service.h         |   7 +-
 .../content/browser/ruleset_version.h         |   4 +
 .../browser/verified_ruleset_dealer.cc        |   4 +
 .../browser/subresource_filter_features.cc    | 116 +-------
 .../core/common/indexed_ruleset.cc            |   5 +-
 .../navigation_throttle_runner.cc             |   5 -
 third_party/blink/common/features.cc          |  12 +-
 39 files changed, 1158 insertions(+), 135 deletions(-)
 create mode 100644 chrome/android/java/res/layout/adblock_editor.xml
 create mode 100644 chrome/android/java/res/xml/adblock_preferences.xml
 create mode 100644 chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockEditor.java
 create mode 100644 chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockPreferences.java
 create mode 100644 components/component_updater/adblock_updater_service.cc
 create mode 100644 components/component_updater/adblock_updater_service.h
 create mode 100644 components/component_updater/download_filters_task.cc
 create mode 100644 components/component_updater/download_filters_task.h

diff --git a/chrome/android/BUILD.gn b/chrome/android/BUILD.gn
--- a/chrome/android/BUILD.gn
+++ b/chrome/android/BUILD.gn
@@ -253,6 +253,7 @@ if (current_toolchain == default_toolchain) {
       "//chrome/android/modules/image_editor/provider:java",
       "//chrome/android/modules/stack_unwinder/provider:java",
       "//chrome/android/webapk/libs/client:client_java",
+      "//chrome/browser/endpoint_fetcher:java",
       "//chrome/android/webapk/libs/common:common_java",
       "//chrome/android/webapk/libs/common:splash_java",
       "//chrome/android/webapk/libs/runtime_library:webapk_service_aidl_java",
diff --git a/chrome/android/chrome_java_sources.gni b/chrome/android/chrome_java_sources.gni
--- a/chrome/android/chrome_java_sources.gni
+++ b/chrome/android/chrome_java_sources.gni
@@ -941,6 +941,8 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/permissions/PermissionSettingsBridge.java",
   "java/src/org/chromium/chrome/browser/permissions/PermissionUpdateRequester.java",
   "java/src/org/chromium/chrome/browser/photo_picker/DecoderServiceImpl.java",
+  "java/src/org/chromium/chrome/browser/settings/AdBlockEditor.java",
+  "java/src/org/chromium/chrome/browser/settings/AdBlockPreferences.java",
   "java/src/org/chromium/chrome/browser/policy/PolicyAuditor.java",
   "java/src/org/chromium/chrome/browser/policy/PolicyAuditorBridge.java",
   "java/src/org/chromium/chrome/browser/prerender/ChromePrerenderServiceImpl.java",
diff --git a/chrome/android/java/res/layout/adblock_editor.xml b/chrome/android/java/res/layout/adblock_editor.xml
new file mode 100644
index 0000000000000000000000000000000000000000..aced0dbca5a2be7e2dc03207a757a6c0c1e654e1
--- /dev/null
+++ b/chrome/android/java/res/layout/adblock_editor.xml
@@ -0,0 +1,67 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2015 The Chromium Authors. All rights reserved.
+     Use of this source code is governed by a BSD-style license that can be
+     found in the LICENSE file. -->
+
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" >
+
+    <ScrollView
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:id="@+id/scroll_view"
+        android:fillViewport="true" >
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:focusableInTouchMode="true" >
+
+            <com.google.android.material.textfield.TextInputLayout
+                android:id="@+id/adblock_url"
+                android:paddingTop="16dp"
+                android:paddingStart="@dimen/pref_autofill_content_spacing"
+                android:paddingEnd="@dimen/pref_autofill_content_spacing"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content" >
+                <!-- TODO(crbug.com/900912): Fix and remove lint ignore -->
+                <EditText
+                    tools:ignore="Autofill"
+                    android:id="@+id/adblock_url_edit"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:inputType="textUri"
+                    android:singleLine="true"
+                    android:hint="@string/options_adblock_edit_label" />
+            </com.google.android.material.textfield.TextInputLayout>
+
+            <Space style="@style/ButtonBarTopSpacer" />
+            <View style="@style/ButtonBarTopDivider" />
+
+            <LinearLayout style="@style/ButtonBar" >
+                <org.chromium.ui.widget.ButtonCompat
+                    android:id="@+id/adblock_reset"
+                    style="@style/ButtonBarButton"
+                    android:text="@string/reset" />
+
+                <org.chromium.ui.widget.ButtonCompat
+                    android:id="@+id/adblock_cancel"
+                    style="@style/ButtonBarButton"
+                    android:text="@string/cancel" />
+
+                <org.chromium.ui.widget.ButtonCompat
+                    android:id="@+id/adblock_save"
+                    style="@style/ButtonBarButton"
+                    android:text="@string/save" />
+            </LinearLayout>
+        </LinearLayout>
+    </ScrollView>
+
+    <include layout="@layout/settings_action_bar_shadow"/>
+
+</FrameLayout>
diff --git a/chrome/android/java/res/values/styles.xml b/chrome/android/java/res/values/styles.xml
--- a/chrome/android/java/res/values/styles.xml
+++ b/chrome/android/java/res/values/styles.xml
@@ -224,6 +224,24 @@ found in the LICENSE file.
         </item>
     </style>
 
+    <style name="ButtonBarTopSpacer" parent="ButtonBarTopSpacerLight">
+        <item name="android:minHeight">5dp</item>
+    </style>
+    <style name="ButtonBar" parent="@android:style/Holo.Light.ButtonBar.AlertDialog">
+        <item name="android:layout_width">match_parent</item>
+        <item name="android:layout_height">wrap_content</item>
+        <item name="android:divider">?android:attr/dividerVertical</item>
+        <item name="android:dividerPadding">0dp</item>
+        <item name="android:showDividers">middle</item>
+    </style>
+    <style name="ButtonBarButton" parent="@style/TextButton">
+        <item name="android:layout_width">0dp</item>
+        <item name="android:layout_height">match_parent</item>
+        <item name="android:layout_weight">1</item>
+        <item name="android:paddingStart">4dp</item>
+        <item name="android:paddingEnd">4dp</item>
+    </style>
+
     <!-- Button bar styles -->
     <style name="ButtonBarTopSpacerLight">
         <item name="android:layout_width">0dp</item>
diff --git a/chrome/android/java/res/values/values.xml b/chrome/android/java/res/values/values.xml
--- a/chrome/android/java/res/values/values.xml
+++ b/chrome/android/java/res/values/values.xml
@@ -27,6 +27,8 @@ found in the LICENSE file.
     <!-- Compositor Tab Title Text -->
     <bool name="compositor_tab_title_fake_bold_text">true</bool>
 
+    <string name="adblock_help_url">https://www.bromite.org/custom-filters</string>
+
     <!-- Download InfoBar animation. -->
     <integer name="download_infobar_fill_in_delay">1200</integer>
     <integer name="download_infobar_fill_out_delay">200</integer>
diff --git a/chrome/android/java/res/xml/adblock_preferences.xml b/chrome/android/java/res/xml/adblock_preferences.xml
new file mode 100644
index 0000000000000000000000000000000000000000..36ea147ed26934ca5d502c3d20c7919027d00f19
--- /dev/null
+++ b/chrome/android/java/res/xml/adblock_preferences.xml
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2015 The Chromium Authors. All rights reserved.
+     Use of this source code is governed by a BSD-style license that can be
+     found in the LICENSE file. -->
+
+<PreferenceScreen
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <org.chromium.components.browser_ui.settings.ChromeSwitchPreference
+        android:key="adblock_switch"
+        android:summaryOn="@string/text_on"
+        android:summaryOff="@string/text_off" />
+
+    <org.chromium.chrome.browser.about_settings.HyperlinkPreference
+        android:key="adblock_help"
+        android:title="@string/adblock_help"
+        app:url="@string/adblock_help_url" />
+
+    <Preference
+        android:key="adblock_edit"
+        android:title="@string/options_adblock_edit_label"
+        android:fragment="org.chromium.chrome.browser.settings.AdBlockEditor" />
+
+</PreferenceScreen>
diff --git a/chrome/android/java/res/xml/main_preferences.xml b/chrome/android/java/res/xml/main_preferences.xml
--- a/chrome/android/java/res/xml/main_preferences.xml
+++ b/chrome/android/java/res/xml/main_preferences.xml
@@ -67,6 +67,11 @@ found in the LICENSE file.
         android:key="safety_check"
         android:order="11"
         android:title="@string/prefs_safety_check"/>
+    <Preference
+        android:fragment="org.chromium.chrome.browser.settings.AdBlockPreferences"
+        android:key="adblock"
+        android:order="13"
+        android:title="@string/prefs_adblock"/>
     <Preference
         android:key="notifications"
         android:order="12"
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockEditor.java b/chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockEditor.java
new file mode 100644
index 0000000000000000000000000000000000000000..bb70f2efdd399b6ebf001cd047e3c2d92f955cdd
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockEditor.java
@@ -0,0 +1,91 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.settings;
+
+import android.os.Bundle;
+import androidx.fragment.app.Fragment;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.EditText;
+
+import org.chromium.components.browser_ui.settings.SettingsUtils;
+import org.chromium.chrome.browser.flags.CachedFeatureFlags;
+import org.chromium.chrome.R;
+import org.chromium.components.url_formatter.UrlFormatter;
+
+/**
+ * Provides the Java-UI for editing AdBlock preferences.
+ */
+public class AdBlockEditor extends Fragment implements TextWatcher {
+    private EditText mAdBlockFiltersUrlEdit;
+    private Button mSaveButton;
+    private Button mResetButton;
+
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+            Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        getActivity().setTitle(R.string.options_adblock_edit_title);
+
+        View v = inflater.inflate(R.layout.adblock_editor, container, false);
+        View scrollView = v.findViewById(R.id.scroll_view);
+        scrollView.getViewTreeObserver().addOnScrollChangedListener(
+                SettingsUtils.getShowShadowOnScrollListener(v, v.findViewById(R.id.shadow)));
+        mAdBlockFiltersUrlEdit = (EditText) v.findViewById(R.id.adblock_url_edit);
+        mAdBlockFiltersUrlEdit.setText(CachedFeatureFlags.getAdBlockFiltersURL());
+        mAdBlockFiltersUrlEdit.addTextChangedListener(this);
+        mAdBlockFiltersUrlEdit.requestFocus();
+
+        initializeSaveCancelResetButtons(v);
+        return v;
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+        mSaveButton.setEnabled(s.length() != 0);
+        mResetButton.setEnabled(true);
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+    }
+
+    private void initializeSaveCancelResetButtons(View v) {
+        mResetButton = (Button) v.findViewById(R.id.adblock_reset);
+        mResetButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                mAdBlockFiltersUrlEdit.setText(CachedFeatureFlags.getAdBlockFiltersURL());
+            }
+        });
+
+        mSaveButton = (Button) v.findViewById(R.id.adblock_save);
+        mSaveButton.setEnabled(false);
+        mSaveButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                CachedFeatureFlags.setAdBlockFiltersURL(
+                        UrlFormatter.fixupUrl(mAdBlockFiltersUrlEdit.getText().toString()).getSpec());
+                getActivity().finish();
+            }
+        });
+
+        Button button = (Button) v.findViewById(R.id.adblock_cancel);
+        button.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                getActivity().finish();
+            }
+        });
+    }
+}
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockPreferences.java b/chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockPreferences.java
new file mode 100644
index 0000000000000000000000000000000000000000..b24689ee7964b82d9394f769172960f4a835e0d0
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/settings/AdBlockPreferences.java
@@ -0,0 +1,61 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.settings;
+
+import android.os.Bundle;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceFragmentCompat;
+import org.chromium.components.browser_ui.settings.ChromeSwitchPreference;
+
+import org.chromium.content_public.browser.BrowserContextHandle;
+import org.chromium.components.browser_ui.site_settings.SiteSettingsPreferenceFragment;
+import org.chromium.components.browser_ui.site_settings.WebsitePreferenceBridge;
+import org.chromium.components.content_settings.ContentSettingsType;
+import org.chromium.components.browser_ui.settings.SettingsUtils;
+import org.chromium.chrome.browser.flags.CachedFeatureFlags;
+import androidx.annotation.VisibleForTesting;
+import org.chromium.chrome.R;
+
+/**
+ * Fragment that allows the user to configure AdBlock related preferences.
+ */
+public class AdBlockPreferences extends SiteSettingsPreferenceFragment {
+    @VisibleForTesting
+    public static final String PREF_ADBLOCK_SWITCH = "adblock_switch";
+    private static final String PREF_ADBLOCK_EDIT = "adblock_edit";
+
+    private Preference mAdBlockEdit;
+
+    @Override
+    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+        getActivity().setTitle(R.string.options_adblock_title);
+        SettingsUtils.addPreferencesFromResource(this, R.xml.adblock_preferences);
+
+        BrowserContextHandle browserContextHandle =
+                getSiteSettingsDelegate().getBrowserContextHandle();
+
+        ChromeSwitchPreference mAdBlockSwitch =
+                (ChromeSwitchPreference) findPreference(PREF_ADBLOCK_SWITCH);
+        boolean isAdBlockEnabled = !WebsitePreferenceBridge.isCategoryEnabled(browserContextHandle, ContentSettingsType.ADS);
+        mAdBlockSwitch.setChecked(isAdBlockEnabled);
+        mAdBlockSwitch.setOnPreferenceChangeListener((preference, newValue) -> {
+            WebsitePreferenceBridge.setCategoryEnabled(browserContextHandle, ContentSettingsType.ADS, !(boolean) newValue);
+            return true;
+        });
+
+        mAdBlockEdit = findPreference(PREF_ADBLOCK_EDIT);
+        updateCurrentAdBlockUrl();
+    }
+
+    private void updateCurrentAdBlockUrl() {
+        mAdBlockEdit.setSummary(CachedFeatureFlags.getAdBlockFiltersURL());
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        updateCurrentAdBlockUrl();
+    }
+}
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelImpl.java
--- a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelImpl.java
@@ -768,7 +768,7 @@ public class TabModelImpl extends TabModelJniBridge {
     protected boolean createTabWithWebContents(
             Tab parent, Profile profile, WebContents webContents) {
         return getTabCreator(profile.isOffTheRecord())
-                .createTabWithWebContents(parent, webContents, TabLaunchType.FROM_RECENT_TABS);
+                .createTabWithWebContents(parent, webContents, TabLaunchType.FROM_LINK);
     }
 
     @Override
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -13152,6 +13152,16 @@ Please help our engineers fix this problem. Tell us what happened right before y
       Never show this again.
     </message>
 
+    <!-- Ad Blocking preferences -->
+    <if expr="is_android">
+      <message name="IDS_OPTIONS_ADBLOCK_TITLE" desc="The title of the Ad Blocking option on Android" formatter_data="android_java">
+        Ad Blocking
+      </message>
+      <message name="IDS_OPTIONS_ADBLOCK_SUMMARY" desc="The title of the Ad Blocking summary on Android" formatter_data="android_java">
+        Configure Ad Blocking and filters URL
+      </message>
+    </if>
+
     <!-- Ad Blocking UI strings. -->
     <message name="IDS_BLOCKED_ADS_PROMPT_TOOLTIP" desc="Explanation that Chrome blocked ads on this site. To be shown as a tooltip on the Ads blocked desktop bubble">
       Ads blocked on this site
diff --git a/chrome/browser/after_startup_task_utils.cc b/chrome/browser/after_startup_task_utils.cc
--- a/chrome/browser/after_startup_task_utils.cc
+++ b/chrome/browser/after_startup_task_utils.cc
@@ -28,6 +28,8 @@
 #include "chromeos/startup/browser_params_proxy.h"
 #endif  // BUILDFLAG(IS_CHROMEOS_LACROS)
 
+#include "chrome/browser/browser_process.h"
+
 using content::BrowserThread;
 
 namespace {
@@ -123,6 +125,8 @@ void SetBrowserStartupIsComplete() {
     ScheduleTask(base::WrapUnique(queued_task));
   g_after_startup_tasks.Get().clear();
   g_after_startup_tasks.Get().shrink_to_fit();
+  // initialize AdBlock engine scheduled updates
+  g_browser_process->adblock_updater()->Start();
 }
 
 // Observes the first visible page load and sets the startup complete
diff --git a/chrome/browser/browser_process.h b/chrome/browser/browser_process.h
--- a/chrome/browser/browser_process.h
+++ b/chrome/browser/browser_process.h
@@ -21,6 +21,7 @@
 #include "build/chromeos_buildflags.h"
 #include "chrome/common/buildflags.h"
 #include "media/media_buildflags.h"
+#include "components/component_updater/adblock_updater_service.h"
 
 class BackgroundModeManager;
 class BrowserProcessPlatformPart;
@@ -71,6 +72,10 @@ namespace component_updater {
 class ComponentUpdateService;
 }
 
+namespace adblock_updater {
+class AdBlockUpdaterService;
+}
+
 namespace extensions {
 class EventRouterForwarder;
 }
@@ -244,6 +249,7 @@ class BrowserProcess {
 #endif
 
   virtual component_updater::ComponentUpdateService* component_updater() = 0;
+  virtual adblock_updater::AdBlockUpdaterService* adblock_updater() = 0;
 
   virtual MediaFileSystemRegistry* media_file_system_registry() = 0;
 
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -1145,6 +1145,26 @@ BrowserProcessImpl::component_updater() {
   return component_updater_.get();
 }
 
+adblock_updater::AdBlockUpdaterService*
+BrowserProcessImpl::adblock_updater() {
+  if (adblock_updater_)
+    return adblock_updater_.get();
+
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI))
+    return nullptr;
+
+  std::unique_ptr<component_updater::UpdateScheduler> scheduler =
+      std::make_unique<component_updater::TimerUpdateScheduler>();
+
+  adblock_updater_ = std::make_unique<adblock_updater::AdBlockUpdaterService>(
+          g_browser_process->system_network_context_manager()->GetSharedURLLoaderFactory(),
+          std::move(scheduler),
+          g_browser_process->subresource_filter_ruleset_service(),
+          local_state()->GetString(prefs::kAdBlockFiltersURL));
+
+  return adblock_updater_.get();
+}
+
 void BrowserProcessImpl::OnKeepAliveStateChanged(bool is_keeping_alive) {
   if (is_keeping_alive)
     Pin();
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -195,6 +195,7 @@ class BrowserProcessImpl : public BrowserProcess,
 #endif
 
   component_updater::ComponentUpdateService* component_updater() override;
+  adblock_updater::AdBlockUpdaterService* adblock_updater() override;
   MediaFileSystemRegistry* media_file_system_registry() override;
   WebRtcLogUploader* webrtc_log_uploader() override;
   network_time::NetworkTimeTracker* network_time_tracker() override;
@@ -382,6 +383,7 @@ class BrowserProcessImpl : public BrowserProcess,
   // to concerns over integrity of data shared between profiles,
   // but some users of component updater only install per-user.
   std::unique_ptr<component_updater::ComponentUpdateService> component_updater_;
+  std::unique_ptr<adblock_updater::AdBlockUpdaterService> adblock_updater_;
 
 #if !BUILDFLAG(IS_ANDROID) && !BUILDFLAG(IS_CHROMEOS)
   // Used to create a singleton instance of SodaInstallerImpl, which can be
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -416,6 +416,9 @@ StartupProfileInfo CreateInitialProfile(
   // missing code in the above test.
   CHECK(profile_info.profile) << "Cannot get default profile.";
 
+  // force AdBlock updater initialisation
+  g_browser_process->adblock_updater();
+
 #else
 #if BUILDFLAG(IS_CHROMEOS_LACROS)
   // Lacros has a special "primary" profile that is tied to the active ChromeOS
diff --git a/chrome/browser/flags/android/cached_feature_flags.cc b/chrome/browser/flags/android/cached_feature_flags.cc
--- a/chrome/browser/flags/android/cached_feature_flags.cc
+++ b/chrome/browser/flags/android/cached_feature_flags.cc
@@ -8,6 +8,9 @@
 
 #include "base/android/jni_string.h"
 #include "base/feature_list.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_service.h"
 #include "content/public/common/content_features.h"
 #include "content/public/common/network_service_util.h"
 
@@ -42,3 +45,11 @@ static jboolean JNI_CachedFeatureFlags_IsNetworkServiceWarmUpEnabled(
   return content::IsOutOfProcessNetworkService() &&
          base::FeatureList::IsEnabled(features::kWarmUpNetworkProcess);
 }
+
+static ScopedJavaLocalRef<jstring> JNI_CachedFeatureFlags_GetAdBlockFiltersURL(JNIEnv* env) {
+  return base::android::ConvertUTF8ToJavaString(env, g_browser_process->local_state()->GetString(prefs::kAdBlockFiltersURL));
+}
+
+static void JNI_CachedFeatureFlags_SetAdBlockFiltersURL(JNIEnv* env, const JavaParamRef<jstring>& url) {
+  g_browser_process->local_state()->SetString(prefs::kAdBlockFiltersURL, base::android::ConvertJavaStringToUTF8(env, url));
+}
diff --git a/chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/CachedFeatureFlags.java b/chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/CachedFeatureFlags.java
--- a/chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/CachedFeatureFlags.java
+++ b/chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/CachedFeatureFlags.java
@@ -186,6 +186,14 @@ public class CachedFeatureFlags {
                 ChromeFeatureList.isEnabled(ChromeFeatureList.BACKGROUND_THREAD_POOL));
     }
 
+     public static void setAdBlockFiltersURL(String url) {
+         CachedFeatureFlagsJni.get().setAdBlockFiltersURL(url);
+     }
+
+     public static String getAdBlockFiltersURL() {
+         return CachedFeatureFlagsJni.get().getAdBlockFiltersURL();
+     }
+
     /**
      * Caches flags that must take effect on startup but are set via native code.
      */
@@ -423,5 +431,7 @@ public class CachedFeatureFlags {
     @NativeMethods
     interface Natives {
         boolean isNetworkServiceWarmUpEnabled();
+        void setAdBlockFiltersURL(String url);
+        String getAdBlockFiltersURL();
     }
 }
diff --git a/chrome/browser/net/system_network_context_manager.cc b/chrome/browser/net/system_network_context_manager.cc
--- a/chrome/browser/net/system_network_context_manager.cc
+++ b/chrome/browser/net/system_network_context_manager.cc
@@ -426,6 +426,8 @@ SystemNetworkContextManager::SystemNetworkContextManager(
       ssl_config_service_manager_(local_state_),
       proxy_config_monitor_(local_state_),
       stub_resolver_config_reader_(local_state_) {
+  local_state_->SetDefaultPrefValue(prefs::kAdBlockFiltersURL,
+                                    base::Value("https://www.bromite.org/filters/filters.dat"));
 #if !BUILDFLAG(IS_ANDROID)
   // QuicAllowed was not part of Android policy.
   const base::Value* value =
@@ -515,6 +517,8 @@ SystemNetworkContextManager::~SystemNetworkContextManager() {
 void SystemNetworkContextManager::RegisterPrefs(PrefRegistrySimple* registry) {
   StubResolverConfigReader::RegisterPrefs(registry);
 
+  registry->RegisterStringPref(prefs::kAdBlockFiltersURL, std::string());
+
   // Static auth params
   registry->RegisterStringPref(prefs::kAuthSchemes,
                                "basic,digest,ntlm,negotiate");

diff --git a/chrome/browser/ui/android/strings/android_chrome_strings.grd b/chrome/browser/ui/android/strings/android_chrome_strings.grd
--- a/chrome/browser/ui/android/strings/android_chrome_strings.grd
+++ b/chrome/browser/ui/android/strings/android_chrome_strings.grd
@@ -212,6 +212,20 @@ CHAR_LIMIT guidelines:
         Advanced
       </message>
 
+      <!-- AdBlock settings -->
+      <message name="IDS_PREFS_ADBLOCK" desc="Title of the AdBlock Settings screen. [CHAR-LIMIT=32]">
+        AdBlock settings
+      </message>
+      <message name="IDS_OPTIONS_ADBLOCK_EDIT_TITLE" desc="The title of the screen that allows users to change the URL that is used to fetch the ad blocker filters.">
+        Edit filters URL
+      </message>
+      <message name="IDS_OPTIONS_ADBLOCK_EDIT_LABEL" desc="The label for the edit text field that allows the user to change the URL that is used to fetch the ad blocker filters.">
+        Filters URL
+      </message>
+      <message name="IDS_ADBLOCK_HELP" desc="The title of the hyperlink that allows users to visit the web page with instructions for custom ad blocker filters.">
+        Visit help page
+      </message>
+
       <!-- Notification channels -->
       <message name="IDS_NOTIFICATION_CATEGORY_GROUP_GENERAL" desc='Subheading for "General" section of a list of notification categories. [CHAR_LIMIT=32]'>
         General
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -2298,6 +2298,9 @@ const char kAudioCaptureAllowed[] = "hardware.audio_capture_enabled";
 // capture devices without prompt.
 const char kAudioCaptureAllowedUrls[] = "hardware.audio_capture_allowed_urls";
 
+// Holds the URL to an indexed subresource filters file.
+const char kAdBlockFiltersURL[] = "adblock.filters_url";
+
 // A pref holding the value of the policy used to explicitly allow or deny
 // access to video capture devices.  When enabled or not set, the user is
 // prompted for device access.  When disabled, access to video capture devices
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -36,6 +36,7 @@ extern const char kDownloadDuplicateFilePromptEnabled[];
 extern const char kForceEphemeralProfiles[];
 extern const char kHomePageIsNewTabPage[];
 extern const char kHomePage[];
+extern const char kAdBlockFiltersURL[];
 extern const char kHttpsOnlyModeEnabled[];
 extern const char kImportantSitesDialogHistory[];
 extern const char kProfileCreationTime[];
diff --git a/components/browser_ui/strings/android/site_settings.grdp b/components/browser_ui/strings/android/site_settings.grdp
--- a/components/browser_ui/strings/android/site_settings.grdp
+++ b/components/browser_ui/strings/android/site_settings.grdp
@@ -358,8 +358,8 @@
   <message name="IDS_INTRUSIVE_ADS_INFORMATION" desc="The extra information at the top of the Site Details page when the site tends to show intrusive ads">
     This site shows intrusive or misleading ads
   </message>
-  <message name="IDS_WEBSITE_SETTINGS_CATEGORY_ADS_BLOCKED" desc="A setting that, if turned on, will block intrusive or misleading ads on sites that have a history of showing such ads.">
-    Block ads on sites that show intrusive or misleading ads
+  <message name="IDS_WEBSITE_SETTINGS_CATEGORY_ADS_BLOCKED" desc="A setting that, if turned on, will block ads.">
+    Block ads based on the current filters
   </message>
   <message name="IDS_WEBSITE_SETTINGS_CATEGORY_ADS_BLOCKED_LIST" desc="Summary text explaining that the Ads permission is set to block ads on some sites. To be shown in the list of permission categories.">
     Blocked on some sites
diff --git a/components/component_updater/BUILD.gn b/components/component_updater/BUILD.gn
--- a/components/component_updater/BUILD.gn
+++ b/components/component_updater/BUILD.gn
@@ -10,6 +10,12 @@ static_library("component_updater") {
     "component_updater_command_line_config_policy.h",
     "component_updater_paths.cc",
     "component_updater_paths.h",
+
+    "adblock_updater_service.cc",
+    "adblock_updater_service.h",
+    "download_filters_task.cc",
+    "download_filters_task.h",
+
     "component_updater_service.cc",
     "component_updater_service.h",
     "component_updater_service_internal.h",
@@ -39,6 +45,7 @@ static_library("component_updater") {
     "//components/prefs",
     "//components/update_client",
     "//components/version_info",
+    "//services/network/public/mojom",
     "//third_party/boringssl:boringssl",
     "//ui/base",
     "//url",
diff --git a/components/component_updater/adblock_updater_service.cc b/components/component_updater/adblock_updater_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4562b2e53da83be94f68b96c139e6d9369330290
--- /dev/null
+++ b/components/component_updater/adblock_updater_service.cc
@@ -0,0 +1,268 @@
+/*
+    This file is part of Bromite.
+
+    Bromite is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Bromite is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Bromite. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "components/component_updater/adblock_updater_service.h"
+
+#include <algorithm>
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/threading/thread_checker.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "url/gurl.h"
+#include "base/strings/safe_sprintf.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+namespace adblock_updater {
+
+// all constants express seconds
+// these could be made configurable
+const int initial_check_delay = 5,
+      next_check_delay = 60*60*24*7, // 1 week
+      on_demand_check_delay = 60; // minimum 1 minute between each on-demand check
+
+AdBlockUpdaterService::AdBlockUpdaterService(scoped_refptr<network::SharedURLLoaderFactory> shared_url_network_factory, std::unique_ptr<component_updater::UpdateScheduler> scheduler,
+   subresource_filter::RulesetService* ruleset_service, std::string filters_url)
+ : ruleset_service_(ruleset_service), shared_url_network_factory_(shared_url_network_factory), scheduler_(std::move(scheduler)) {
+  DCHECK(ruleset_service);
+
+  filters_url_ = filters_url;
+}
+
+AdBlockUpdaterService::~AdBlockUpdaterService() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+void AdBlockUpdaterService::AddObserver(Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observer_list_.AddObserver(observer);
+}
+
+void AdBlockUpdaterService::RemoveObserver(Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observer_list_.RemoveObserver(observer);
+}
+
+void AdBlockUpdaterService::NotifyObservers(Event event) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (auto& observer : observer_list_)
+    observer.OnEvent(event);
+}
+
+void AdBlockUpdaterService::Start() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // avoid multiple scheduling
+  if (scheduled_)
+    return;
+  scheduled_ = true;
+
+  LOG(INFO) << "AdBlockUpdaterService: starting up. "
+          << "First update attempt will take place in "
+          << initial_check_delay << " seconds. "
+          << "Next update attempt will take place in "
+          << next_check_delay << " seconds. ";
+
+  scheduler_->Schedule(
+      base::Seconds(initial_check_delay),
+      base::Seconds(next_check_delay),
+      base::BindRepeating(&AdBlockUpdaterService::OnDemandScheduledUpdate,
+                 base::Unretained(this)), base::DoNothing());
+}
+
+void AdBlockUpdaterService::OnDemandScheduledUpdate(component_updater::UpdateScheduler::OnFinishedCallback on_finished) {
+  //TODO: call on_finished
+  OnDemandUpdateAsNeeded(false, Callback());
+}
+
+bool AdBlockUpdaterService::OnDemandUpdate(Callback on_finished) {
+  return OnDemandUpdateAsNeeded(true, std::move(on_finished));
+}
+
+bool AdBlockUpdaterService::OnDemandUpdateAsNeeded(bool is_foreground, Callback on_finished) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // Check if the request is too early
+  if (!last_update_.is_null()) {
+    base::TimeDelta delta =
+        base::TimeTicks::Now() - last_update_;
+    if (delta < base::Seconds(on_demand_check_delay)) {
+      LOG(INFO) << "AdBlockUpdaterService: update not necessary.";
+      return false;
+    }
+  }
+
+  if (is_updating_) {
+    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+        FROM_HERE, base::BindOnce(std::move(on_finished),
+                                    Error::UPDATE_IN_PROGRESS));
+    return false;
+  }
+  is_updating_ = true;
+
+  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+      FROM_HERE, base::BindOnce(&AdBlockUpdaterService::NotifyObservers, base::Unretained(this), Event::ADBLOCK_CHECKING_FOR_UPDATES));
+
+  base::Time::Exploded e = {0};
+  base::Time min_last_modified = base::Time();
+  auto version = ruleset_service_->GetMostRecentlyIndexedVersion();
+  LOG(INFO) << "AdBlockUpdaterService: MostRecentIndexedVersion = " << version.content_version;
+  std::vector<std::string> tokens =
+      base::SplitString(version.content_version, ".", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+  int i = 0;
+  bool failed = false;
+  for (const std::string& token : tokens) {
+    // parse as number
+    int n = 0;
+    if (!base::StringToInt(token, &n)) {
+      failed = true;
+      break;
+    }
+
+    switch (i++) {
+      case 0:
+        e.year = 2019 + n;
+        break;
+      case 1:
+        e.month = n + 1;
+        break;
+      case 2:
+        e.day_of_month = n + 1;
+        break;
+      case 3:
+        e.second = n % 60;
+        n -= e.second;
+        n /= 60;
+        e.minute = n % 60;
+        e.hour = n / 60;
+        break;
+      default:
+        failed = true;
+        break;
+    }
+  }
+
+  if (failed) {
+    LOG(WARNING) << "AdBlockUpdaterService: failed to parse most recent version as x.y.z.w dot-separated integers";
+  } else {
+    if (!base::Time::FromUTCExploded(e, &min_last_modified))
+      LOG(WARNING) << "AdBlockUpdaterService: failed to convert version to time.";
+  }
+
+  // avoid making a new request if version-based time is recent enough
+  if (!failed) {
+    base::TimeDelta delta =
+        base::Time::Now() - min_last_modified;
+    if (delta < base::Seconds(on_demand_check_delay)) {
+      LOG(INFO) << "AdBlockUpdaterService: update check not yet needed.";
+      is_updating_ = false;
+      return false;
+    }
+  }
+
+  last_update_ = base::TimeTicks::Now();
+  auto task = base::MakeRefCounted<DownloadFiltersTask>(
+      shared_url_network_factory_,
+      is_foreground, filters_url_,
+      min_last_modified,
+      base::BindOnce(&AdBlockUpdaterService::OnUpdateComplete, base::Unretained(this),
+                     std::move(on_finished)));
+
+  // run task now; task is responsible for downloading the filters (if Last-Modified header is more recent)
+  // and then clearing the 'is_updating' status
+  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(FROM_HERE,
+      base::BindOnce(&DownloadFiltersTask::Run, base::Unretained(task.get())));
+  tasks_.insert(task);
+
+  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+      FROM_HERE, base::BindOnce(&AdBlockUpdaterService::NotifyObservers, base::Unretained(this), Event::ADBLOCK_UPDATE_DOWNLOADING));
+
+  return true;
+}
+
+void AdBlockUpdaterService::OnUpdateComplete(Callback on_finished,
+                                        scoped_refptr<DownloadFiltersTask> task,
+                                        Error error) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto file_path = task->file_path();
+  if (error == Error::NONE) {
+    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+        FROM_HERE, base::BindOnce(&AdBlockUpdaterService::NotifyObservers, base::Unretained(this), Event::ADBLOCK_UPDATE_READY));
+
+    subresource_filter::UnindexedRulesetInfo ruleset_info;
+    ruleset_info.ruleset_path = file_path;
+    ruleset_info.delete_ruleset_path = true;
+    ruleset_info.content_version = "0.0.0.0";
+    DCHECK(!ruleset_info.ruleset_path.empty());
+
+    // convert Last-Modified timestamp fetched by the DownloadFiltersTask to a semver version
+    auto t = task->last_modified();
+    bool ignore_version = t.is_null();
+    if (!ignore_version) {
+      base::Time::Exploded e;
+      t.UTCExplode(&e);
+
+      // convert time to version
+      const int major = e.year - 2019,
+                minor = e.month - 1,
+                patch = e.day_of_month - 1,
+                revision = (e.hour*60+e.minute)*60 + e.second;
+      if (major < 0)
+         LOG(WARNING) << "AdBlockUpdaterService: too old Last-Modified header, ignoring version check.";
+      else {
+        char version_buffer[32];
+        base::strings::SafeSNPrintf(version_buffer, sizeof(version_buffer), "%d.%d.%d.%d",
+                                major, minor, patch, revision);
+
+        ruleset_info.content_version = version_buffer;
+
+        LOG(INFO) << "AdBlockUpdaterService: indexing filters with version " << ruleset_info.content_version;
+      }
+    } else
+      LOG(WARNING) << "AdBlockUpdaterService: invalid Last-Modified header, ignoring version check.";
+    ruleset_service_->IndexAndStoreAndPublishRulesetIfNeeded(ruleset_info, ignore_version);
+
+    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+        FROM_HERE, base::BindOnce(&AdBlockUpdaterService::NotifyObservers, base::Unretained(this), Event::ADBLOCK_UPDATED));
+  } else if (error == Error::UPDATE_NOT_NEEDED) {
+    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+        FROM_HERE, base::BindOnce(&AdBlockUpdaterService::NotifyObservers, base::Unretained(this), Event::ADBLOCK_NOT_UPDATED));
+  } else {
+    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+        FROM_HERE, base::BindOnce(&AdBlockUpdaterService::NotifyObservers, base::Unretained(this), Event::ADBLOCK_UPDATE_ERROR));
+  }
+
+  //TODO: run these only when index-and-store is actually finished?
+  // would require exposing the callback in IndexAndStoreAndPublishRulesetIfNeeded
+  if (!on_finished.is_null()) {
+    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+        FROM_HERE, base::BindOnce(std::move(on_finished), error));
+  }
+
+  // mark as not updating
+  is_updating_ = false;
+  tasks_.erase(task);
+}
+
+}  // namespace adblock_updater
diff --git a/components/component_updater/adblock_updater_service.h b/components/component_updater/adblock_updater_service.h
new file mode 100644
index 0000000000000000000000000000000000000000..d581ab59588515a69a4d4a2ef5c875f5587c93e2
--- /dev/null
+++ b/components/component_updater/adblock_updater_service.h
@@ -0,0 +1,98 @@
+/*
+    This file is part of Bromite.
+
+    Bromite is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Bromite is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Bromite. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#ifndef COMPONENTS_ADBLOCK_UPDATER_SERVICE_H
+#define COMPONENTS_ADBLOCK_UPDATER_SERVICE_H
+
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
+#include "base/version.h"
+#include "build/build_config.h"
+#include "components/component_updater/update_scheduler.h"
+#include "url/gurl.h"
+#include "components/component_updater/download_filters_task.h"
+#include "components/subresource_filter/content/browser/ruleset_service.h"
+#include "services/network/public/cpp/shared_url_loader_factory.h"
+
+namespace adblock_updater {
+
+// Called when a non-blocking call in this module completes.
+using Callback = base::OnceCallback<void(Error error)>;
+
+class Observer {
+   public:
+    virtual ~Observer() {}
+
+    // Called by the update service when a state change happens.
+    virtual void OnEvent(Event event) = 0;
+};
+
+// The AdBlock update service is in charge of downloading and saving the
+// AdBlock filters.
+//
+// All methods are safe to call ONLY from the browser's main thread.
+class AdBlockUpdaterService {
+ public:
+  AdBlockUpdaterService(scoped_refptr<network::SharedURLLoaderFactory> shared_url_network_factory, std::unique_ptr<component_updater::UpdateScheduler> scheduler,
+                        subresource_filter::RulesetService* ruleset_service, std::string filters_url);
+  ~AdBlockUpdaterService();
+
+  // Adds an observer for this class. An observer should not be added more
+  // than once. The caller retains the ownership of the observer object.
+  void AddObserver(Observer* observer);
+
+  // Removes an observer. It is safe for an observer to be removed while
+  // the observers are being notified.
+  void RemoveObserver(Observer* observer);
+
+  // Will schedule automatic updates, run in background.
+  void Start();
+
+  // To be called for an user-triggered update.
+  // Will not result in an actual update if the last update was too recently triggered.
+  bool OnDemandUpdate(Callback on_finished);
+
+ private:
+  void NotifyObservers(Event event);
+  void OnDemandScheduledUpdate(component_updater::UpdateScheduler::OnFinishedCallback on_finished);
+  bool OnDemandUpdateAsNeeded(bool is_foreground, Callback on_finished);
+  void OnUpdateComplete(Callback callback, scoped_refptr<DownloadFiltersTask> task, Error error);
+
+  base::ObserverList<Observer>::Unchecked observer_list_;
+  base::ThreadChecker thread_checker_;
+  base::TimeTicks last_update_;
+
+  subresource_filter::RulesetService* ruleset_service_;
+  std::string filters_url_;
+
+  scoped_refptr<network::SharedURLLoaderFactory> shared_url_network_factory_;
+  std::unique_ptr<component_updater::UpdateScheduler> scheduler_;
+
+  bool is_updating_ = false;
+  bool scheduled_ = false;
+  std::set<scoped_refptr<DownloadFiltersTask>> tasks_;
+};
+
+}  // namespace adblock_updater
+
+#endif  // COMPONENTS_ADBLOCK_UPDATER_SERVICE_H
diff --git a/components/component_updater/download_filters_task.cc b/components/component_updater/download_filters_task.cc
new file mode 100644
index 0000000000000000000000000000000000000000..69bed5f7b7b790207699fd54afed547527cdde82
--- /dev/null
+++ b/components/component_updater/download_filters_task.cc
@@ -0,0 +1,222 @@
+/*
+    This file is part of Bromite.
+
+    Bromite is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Bromite is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Bromite. If not, see <https://www.gnu.org/licenses/>.
+*/
+#include "components/component_updater/download_filters_task.h"
+
+#include <utility>
+
+#include "base/files/file_util.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "net/base/load_flags.h"
+#include "url/gurl.h"
+#include "services/network/public/cpp/resource_request.h"
+#include "services/network/public/mojom/url_response_head.mojom.h"
+
+namespace adblock_updater {
+
+// maximum 10MB for the filters file
+const int kMaxBodySize = 1024 * 1024 * 10;
+
+const int kMaxRetriesOnNetworkChange = 3;
+
+const net::NetworkTrafficAnnotationTag traffic_annotation =
+    net::DefineNetworkTrafficAnnotation("update_client", R"(
+        semantics {
+          sender: "Bromite AdBlock filters updater"
+          description:
+            "The AdBlock filters updater is responsible for updating the subresource filters."
+          trigger: "Manual or automatic AdBlock filters updates."
+          data:
+            "Subresource filters rulesets, binary format"
+          destination: WEBSITE
+        }
+        )");
+
+DownloadFiltersTask::DownloadFiltersTask(scoped_refptr<network::SharedURLLoaderFactory> shared_url_network_factory,
+                       bool is_foreground, const std::string& filters_url, base::Time min_last_modified,
+                       Callback callback)
+    : shared_url_network_factory_(shared_url_network_factory),
+      is_foreground_(is_foreground),
+      complete_callback_(std::move(callback)) {
+  DCHECK(!filters_url.empty());
+  filters_url_ = GURL(filters_url);
+  min_last_modified_ = min_last_modified;
+
+  if (filters_url.empty()) {
+    return;
+  }
+
+  createSimpleURLLoader(!min_last_modified_.is_null());
+}
+
+void DownloadFiltersTask::createSimpleURLLoader(bool headers_only) {
+  // always reset response-related fields
+  response_code_ = -1;
+  final_url_ = GURL();
+  download_start_time_ = base::TimeTicks();
+
+  auto resource_request = std::make_unique<network::ResourceRequest>();
+  resource_request->url = filters_url_;
+  resource_request->credentials_mode = network::mojom::CredentialsMode::kOmit;
+  resource_request->load_flags = net::LOAD_BYPASS_CACHE | net::LOAD_DISABLE_CACHE | net::LOAD_DO_NOT_SAVE_COOKIES;
+  resource_request->credentials_mode = network::mojom::CredentialsMode::kOmit;
+  if (headers_only)
+    // will chain two requests - first one is to check last modified header alone
+    resource_request->method = "HEAD";
+  else
+    resource_request->method = "GET";
+
+  simple_url_loader_ = network::SimpleURLLoader::Create(
+      std::move(resource_request), traffic_annotation);
+  simple_url_loader_->SetRetryOptions(
+      kMaxRetriesOnNetworkChange,
+      network::SimpleURLLoader::RetryMode::RETRY_ON_NETWORK_CHANGE);
+  simple_url_loader_->SetAllowPartialResults(false);
+  simple_url_loader_->SetOnResponseStartedCallback(base::BindOnce(
+      &DownloadFiltersTask::OnResponseStarted, base::Unretained(this)));
+}
+
+DownloadFiltersTask::~DownloadFiltersTask() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+void DownloadFiltersTask::Run() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // will not be initialized if the URL was empty
+  if (!simple_url_loader_) {
+    TaskComplete(Error::INVALID_ARGUMENT);
+    return;
+  }
+
+  download_start_time_ = base::TimeTicks::Now();
+  if (min_last_modified_.is_null()) {
+    internalDownload();
+  } else {
+    simple_url_loader_->DownloadHeadersOnly(
+      shared_url_network_factory_.get(),
+      base::BindOnce(&DownloadFiltersTask::OnHeadersDownloadComplete, base::Unretained(this))
+    );
+  }
+}
+
+void DownloadFiltersTask::internalDownload() {
+  simple_url_loader_->DownloadToTempFile(
+      shared_url_network_factory_.get(),
+      base::BindOnce(&DownloadFiltersTask::OnDownloadComplete, base::Unretained(this)),
+      kMaxBodySize);
+}
+
+void DownloadFiltersTask::OnHeadersDownloadComplete(scoped_refptr<net::HttpResponseHeaders> headers) {
+  // something went wrong
+  if (headers == nullptr) {
+    OnDownloadComplete(base::FilePath());
+    return;
+  }
+
+  // ignoring 'headers' as 'Last-Modified' has already been picked up by OnResponseStarted
+  const base::TimeDelta dt =
+          last_modified_ - min_last_modified_;
+
+  if (dt.InSeconds() > 0) {
+    // prepare for next simple URL loader and trigger download
+    createSimpleURLLoader(false);
+    internalDownload();
+    return;
+  }
+
+  // the remote filters are not more recent than known ones
+  TaskComplete(Error::UPDATE_NOT_NEEDED);
+}
+
+void DownloadFiltersTask::OnResponseStarted(
+    const GURL& final_url,
+    const network::mojom::URLResponseHead& response_head) {
+
+  final_url_ = final_url;
+  response_code_ = response_head.headers ? response_head.headers->response_code() : -1;
+
+  if (!response_head.headers->GetLastModifiedValue(&last_modified_))
+    LOG(WARNING) << "DownloadFiltersTask: fetching URL '" << final_url.spec() << "' with method " << (min_last_modified_.is_null() ? "GET" : "HEAD") << " (no Last-Modified header)";
+  else
+    LOG(INFO) << "DownloadFiltersTask: fetching URL '" << final_url.spec() << "' with method " << (min_last_modified_.is_null() ? "GET" : "HEAD");
+}
+
+void DownloadFiltersTask::OnDownloadComplete(base::FilePath file_path) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  int net_error = simple_url_loader_->NetError();
+  int64_t content_size = simple_url_loader_->GetContentSize();
+
+  const base::TimeTicks download_end_time(base::TimeTicks::Now());
+  const base::TimeDelta download_time =
+      download_end_time >= download_start_time_
+          ? download_end_time - download_start_time_
+          : base::TimeDelta();
+
+  // Consider a 5xx response from the server as an indication to terminate
+  // the request and avoid overloading the server in this case.
+  // is not accepting requests for the moment.
+  int error = -1;
+  if (!file_path.empty() && response_code_ == 200) {
+    DCHECK_EQ(0, net_error);
+    error = 0;
+  } else if (response_code_ != -1) {
+    error = response_code_;
+  } else {
+    error = net_error;
+  }
+
+  LOG(INFO) << "DownloadFiltersTask: downloaded " << content_size << " bytes in "
+          << download_time.InMilliseconds() << "ms from '" << final_url_.spec()
+          << "' to '" << file_path << "' with net_error " << net_error << " and error " << error;
+
+  if (error) {
+    TaskComplete(Error::DOWNLOAD_ERROR);
+    return;
+  }
+
+  file_path_ = file_path;
+  TaskComplete(Error::NONE);
+}
+
+void DownloadFiltersTask::Cancel() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  LOG(INFO) << "DownloadFiltersTask: update cancelled";
+
+  // deletion of the simple_url_loader_ will cause cancellation of its active request, if any
+
+  TaskComplete(Error::UPDATE_CANCELED);
+}
+
+void DownloadFiltersTask::TaskComplete(Error error) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
+      FROM_HERE, base::BindOnce(std::move(complete_callback_),
+                                scoped_refptr<DownloadFiltersTask>(this), error));
+}
+
+base::Time DownloadFiltersTask::last_modified() {
+  return last_modified_;
+}
+
+base::FilePath DownloadFiltersTask::file_path() {
+  return file_path_;
+}
+
+}  // namespace adblock_updater
diff --git a/components/component_updater/download_filters_task.h b/components/component_updater/download_filters_task.h
new file mode 100644
index 0000000000000000000000000000000000000000..e5aeb7c9a7f1f2b8e71c6345edfcbd6f7d13d704
--- /dev/null
+++ b/components/component_updater/download_filters_task.h
@@ -0,0 +1,129 @@
+/*
+    This file is part of Bromite.
+
+    Bromite is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Bromite is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Bromite. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#ifndef COMPONENTS_DOWNLOAD_FILTERS_TASK_H_
+#define COMPONENTS_DOWNLOAD_FILTERS_TASK_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/threading/thread_checker.h"
+#include "components/update_client/network.h"
+#include "url/gurl.h"
+#include "base/files/file_path.h"
+#include "services/network/public/cpp/shared_url_loader_factory.h"
+#include "services/network/public/cpp/simple_url_loader.h"
+
+namespace adblock_updater {
+
+// Errors generated as a result of calling Run() or by the service itself (UPDATE_IN_PROGRESS or UPDATE_CANCELED)
+enum class Error {
+  NONE = 0,
+  UPDATE_IN_PROGRESS = 1,
+  UPDATE_CANCELED = 2,
+  UPDATE_NOT_NEEDED = 3,
+  DOWNLOAD_ERROR = 4,
+  INVALID_ARGUMENT = 5,
+  MAX_VALUE,
+};
+
+enum class Event {
+      // Sent before the update client does an update check.
+      ADBLOCK_CHECKING_FOR_UPDATES = 1,
+
+      // Sent after the new filters have been downloaded but before the install
+      // or the upgrade is attempted.
+      ADBLOCK_UPDATE_READY,
+
+      // Sent when filters are being downloaded.
+      ADBLOCK_UPDATE_DOWNLOADING,
+
+      // Sent when filters have been successfully updated.
+      ADBLOCK_UPDATED,
+
+      // Sent when filters have not been updated because there
+      // was no new version available
+      //TODO: implement this with the headers check
+      ADBLOCK_NOT_UPDATED,
+
+      // Sent when an error ocurred during an update for any reason, including
+      // the update check itself failed, or the download of the update payload
+      // failed, or applying the update failed.
+      ADBLOCK_UPDATE_ERROR,
+};
+
+// Defines a specialized task for updating AdBlock filters.
+class DownloadFiltersTask : public base::RefCounted<DownloadFiltersTask> {
+ public:
+  DownloadFiltersTask(const DownloadFiltersTask&) = delete;
+  DownloadFiltersTask& operator=(const DownloadFiltersTask&) = delete;
+
+  using Callback =
+      base::OnceCallback<void(scoped_refptr<DownloadFiltersTask> task, Error error)>;
+
+  // |shared_url_network_factory| is injected here for the URL loader factory.
+  // |is_foreground| is true when the update task is initiated by the user.
+  // |filters_url| is the URL to load filters from.
+  // |complete_callback| is called to return the execution flow back to creator of
+  //    this task when the task is done.
+  DownloadFiltersTask(scoped_refptr<network::SharedURLLoaderFactory> shared_url_network_factory,
+                       bool is_foreground, const std::string& filters_url, base::Time min_last_modified,
+                       Callback complete_callback);
+
+  void Run();
+
+  void Cancel();
+
+  base::FilePath file_path();
+
+  base::Time last_modified();
+
+ private:
+  ~DownloadFiltersTask();
+
+  void OnDownloadProgress(uint64_t current);
+  void OnResponseStarted(const GURL& final_url,
+                         const network::mojom::URLResponseHead& response_head);
+  void OnDownloadComplete(base::FilePath file_path);
+  void OnHeadersDownloadComplete(scoped_refptr<net::HttpResponseHeaders> headers);
+  void createSimpleURLLoader(bool);
+  void internalDownload();
+
+  // Called when the task has completed either because the task has run or
+  // it has been canceled.
+  void TaskComplete(Error error);
+
+  base::ThreadChecker thread_checker_;
+  scoped_refptr<network::SharedURLLoaderFactory> shared_url_network_factory_;
+  const bool is_foreground_;
+  Callback complete_callback_;
+  std::unique_ptr<network::SimpleURLLoader> simple_url_loader_;
+
+  // fields populated while downloading
+  base::TimeTicks download_start_time_;
+  GURL final_url_, filters_url_;
+  int response_code_;
+  base::Time last_modified_, min_last_modified_;
+  base::FilePath file_path_;
+
+  friend class base::RefCounted<DownloadFiltersTask>;
+};
+
+}  // namespace update_client
+
+#endif  // COMPONENTS_DOWNLOAD_FILTERS_TASK_H_
diff --git a/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc b/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
--- a/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
+++ b/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
@@ -667,6 +667,17 @@ ContentSubresourceFilterThrottleManager::
       throttle->NotifyPageActivationWithRuleset(EnsureRulesetHandle(),
                                                 ad_tagging_state);
     }
+
+    //TODO: could use same logic as in SubresourceFilterSafeBrowsingActivationThrottle::NotifyResult()
+    {
+      subresource_filter::ActivationDecision ignored_decision;
+      mojom::ActivationState ad_filtering_state;
+      ad_filtering_state.activation_level = profile_interaction_manager_->OnPageActivationComputed(
+	      navigation_handle, mojom::ActivationLevel::kEnabled, &ignored_decision);
+      throttle->NotifyPageActivationWithRuleset(EnsureRulesetHandle(),
+                                                ad_filtering_state);
+    }
+
     return throttle;
   }
 
diff --git a/components/subresource_filter/content/browser/ruleset_service.cc b/components/subresource_filter/content/browser/ruleset_service.cc
--- a/components/subresource_filter/content/browser/ruleset_service.cc
+++ b/components/subresource_filter/content/browser/ruleset_service.cc
@@ -46,9 +46,7 @@ namespace {
 
 void RecordIndexAndWriteRulesetResult(
     RulesetService::IndexAndWriteRulesetResult result) {
-  UMA_HISTOGRAM_ENUMERATION(
-      "SubresourceFilter.WriteRuleset.Result", static_cast<int>(result),
-      static_cast<int>(RulesetService::IndexAndWriteRulesetResult::MAX));
+  VLOG(1) << "SubresourceFilter.WriteRuleset.Result: " << static_cast<int>(result);
 }
 
 // Implements operations on a `sentinel file`, which is used as a safeguard to
@@ -228,10 +226,13 @@ RulesetService::RulesetService(
 RulesetService::~RulesetService() {}
 
 void RulesetService::IndexAndStoreAndPublishRulesetIfNeeded(
-    const UnindexedRulesetInfo& unindexed_ruleset_info) {
-  if (unindexed_ruleset_info.content_version.empty())
+    const UnindexedRulesetInfo& unindexed_ruleset_info, bool ignore_recent_version) {
+  if (unindexed_ruleset_info.content_version.empty()) {
+    LOG(INFO) << "RulesetService: ignoring update with empty version.";
     return;
+  }
 
+  if (!ignore_recent_version) {
   // Trying to store a ruleset with the same version for a second time would
   // not only be futile, but would fail on Windows due to "File System
   // Tunneling" as long as the previously stored copy of the rules is still
@@ -241,13 +242,16 @@ void RulesetService::IndexAndStoreAndPublishRulesetIfNeeded(
   if (most_recently_indexed_version.IsCurrentFormatVersion() &&
       most_recently_indexed_version.content_version ==
           unindexed_ruleset_info.content_version) {
+    LOG(INFO) << "RulesetService: ignoring update with equal or older version.";
     return;
   }
+  }
 
   // Before initialization, retain information about the most recently supplied
   // unindexed ruleset, to be processed during initialization.
   if (!is_initialized_) {
     queued_unindexed_ruleset_info_ = unindexed_ruleset_info;
+    LOG(INFO) << "RulesetService: ignoring update while not initialized.";
     return;
   }
 
@@ -266,6 +270,18 @@ IndexedRulesetVersion RulesetService::GetMostRecentlyIndexedVersion() const {
 IndexedRulesetVersion RulesetService::IndexAndWriteRuleset(
     const base::FilePath& indexed_ruleset_base_dir,
     const UnindexedRulesetInfo& unindexed_ruleset_info) {
+  IndexedRulesetVersion version = IndexAndWriteRulesetInternal(indexed_ruleset_base_dir, unindexed_ruleset_info);
+  // cleanup temporary file when done
+  if (unindexed_ruleset_info.delete_ruleset_path) {
+    base::DeleteFile(unindexed_ruleset_info.ruleset_path);
+  }
+  return version;
+}
+
+// static
+IndexedRulesetVersion RulesetService::IndexAndWriteRulesetInternal(
+    const base::FilePath& indexed_ruleset_base_dir,
+    const UnindexedRulesetInfo& unindexed_ruleset_info) {
   base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
                                                 base::BlockingType::MAY_BLOCK);
 
@@ -273,6 +289,7 @@ IndexedRulesetVersion RulesetService::IndexAndWriteRuleset(
       unindexed_ruleset_info);
 
   if (!unindexed_ruleset_stream_generator.ruleset_stream()) {
+    LOG(WARNING) << "RulesetService: failed to open: " << unindexed_ruleset_info.ruleset_path;
     RecordIndexAndWriteRulesetResult(
         IndexAndWriteRulesetResult::FAILED_OPENING_UNINDEXED_RULESET);
     return IndexedRulesetVersion();
@@ -286,6 +303,7 @@ IndexedRulesetVersion RulesetService::IndexAndWriteRuleset(
           indexed_ruleset_base_dir, indexed_version);
 
   if (!base::CreateDirectory(indexed_ruleset_version_dir)) {
+    LOG(WARNING) << "RulesetService: failed to create version dir: " << indexed_ruleset_version_dir;
     RecordIndexAndWriteRulesetResult(
         IndexAndWriteRulesetResult::FAILED_CREATING_VERSION_DIR);
     return IndexedRulesetVersion();
@@ -311,6 +329,7 @@ IndexedRulesetVersion RulesetService::IndexAndWriteRuleset(
 
   RulesetIndexer indexer;
   if (!(*g_index_ruleset_func)(&unindexed_ruleset_stream_generator, &indexer)) {
+    LOG(WARNING) << "RulesetService: failed parsing.";
     RecordIndexAndWriteRulesetResult(
         IndexAndWriteRulesetResult::FAILED_PARSING_UNINDEXED_RULESET);
     return IndexedRulesetVersion();
@@ -331,6 +350,8 @@ IndexedRulesetVersion RulesetService::IndexAndWriteRuleset(
   if (result != IndexAndWriteRulesetResult::SUCCESS)
     return IndexedRulesetVersion();
 
+  LOG(INFO) << "RulesetService: successful parsing.";
+
   DCHECK(indexed_version.IsValid());
   return indexed_version;
 }
@@ -453,6 +474,7 @@ void RulesetService::IndexAndStoreRuleset(
 void RulesetService::OnWrittenRuleset(WriteRulesetCallback result_callback,
                                       const IndexedRulesetVersion& version) {
   DCHECK(!result_callback.is_null());
+  LOG(INFO) << "RulesetService: valid version: " << version.IsValid();
   if (!version.IsValid())
     return;
   version.SaveToPrefs(local_state_);
@@ -465,7 +487,6 @@ void RulesetService::OpenAndPublishRuleset(
       IndexedRulesetLocator::GetRulesetDataFilePath(
           IndexedRulesetLocator::GetSubdirectoryPathForVersion(
               indexed_ruleset_base_dir_, version));
-
   publisher_->TryOpenAndSetRulesetFile(
       file_path, version.checksum,
       base::BindOnce(&RulesetService::OnRulesetSet, AsWeakPtr()));
diff --git a/components/subresource_filter/content/browser/ruleset_service.h b/components/subresource_filter/content/browser/ruleset_service.h
--- a/components/subresource_filter/content/browser/ruleset_service.h
+++ b/components/subresource_filter/content/browser/ruleset_service.h
@@ -184,7 +184,7 @@ class RulesetService : public base::SupportsWeakPtr<RulesetService> {
   //
   // Virtual so that it can be mocked out in tests.
   virtual void IndexAndStoreAndPublishRulesetIfNeeded(
-      const UnindexedRulesetInfo& unindexed_ruleset_info);
+      const UnindexedRulesetInfo& unindexed_ruleset_info, bool ignore_recent_version = false);
 
   // Get the ruleset version associated with the current local_state_.
   IndexedRulesetVersion GetMostRecentlyIndexedVersion() const;
@@ -217,6 +217,11 @@ class RulesetService : public base::SupportsWeakPtr<RulesetService> {
       const base::FilePath& indexed_ruleset_base_dir,
       const UnindexedRulesetInfo& unindexed_ruleset_info);
 
+  // internal function used to wrap the temporary file deletion for unindexed rulesets
+  static IndexedRulesetVersion IndexAndWriteRulesetInternal(
+      const base::FilePath& indexed_ruleset_base_dir,
+      const UnindexedRulesetInfo& unindexed_ruleset_info);
+
   // Reads the rules via the |unindexed_ruleset_stream_generator|, and indexes
   // them using |indexer|. Returns whether the entire ruleset could be parsed.
   static bool IndexRuleset(
diff --git a/components/subresource_filter/content/browser/ruleset_version.h b/components/subresource_filter/content/browser/ruleset_version.h
--- a/components/subresource_filter/content/browser/ruleset_version.h
+++ b/components/subresource_filter/content/browser/ruleset_version.h
@@ -53,6 +53,10 @@ struct UnindexedRulesetInfo {
   // can be indicated not only by setting |license_path| to empty, but also by
   // setting it to any non existent path.
   base::FilePath license_path;
+
+  // Whether to delete or not the ruleset path once done indexing; useful for disposal
+  // of temporary files.
+  bool delete_ruleset_path;
 };
 
 // Encapsulates the combination of the binary format version of the indexed
diff --git a/components/subresource_filter/content/browser/verified_ruleset_dealer.cc b/components/subresource_filter/content/browser/verified_ruleset_dealer.cc
--- a/components/subresource_filter/content/browser/verified_ruleset_dealer.cc
+++ b/components/subresource_filter/content/browser/verified_ruleset_dealer.cc
@@ -11,6 +11,7 @@
 #include "base/functional/bind.h"
 #include "base/functional/callback_helpers.h"
 #include "base/location.h"
+#include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/notreached.h"
 #include "base/task/sequenced_task_runner.h"
@@ -39,6 +40,9 @@ RulesetFilePtr VerifiedRulesetDealer::OpenAndSetRulesetFile(
   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("loading"),
                "VerifiedRulesetDealer::OpenAndSetRulesetFile", "file_valid",
                file->IsValid());
+
+  LOG(INFO) << "OpenAndSetRulesetFile: " << file_path << " is valid: " << file->IsValid();
+
   if (file->IsValid()) {
     SetRulesetFile(file->Duplicate());
     expected_checksum_ = expected_checksum;
diff --git a/components/subresource_filter/core/browser/subresource_filter_features.cc b/components/subresource_filter/core/browser/subresource_filter_features.cc
--- a/components/subresource_filter/core/browser/subresource_filter_features.cc
+++ b/components/subresource_filter/core/browser/subresource_filter_features.cc
@@ -54,72 +54,7 @@ class CommaSeparatedStrings {
   const std::vector<base::StringPiece> pieces_;
 };
 
-std::string TakeVariationParamOrReturnEmpty(
-    std::map<std::string, std::string>* params,
-    const std::string& key) {
-  auto it = params->find(key);
-  if (it == params->end())
-    return std::string();
-  std::string value = std::move(it->second);
-  params->erase(it);
-  return value;
-}
-
-mojom::ActivationLevel ParseActivationLevel(
-    const base::StringPiece activation_level) {
-  if (base::EqualsCaseInsensitiveASCII(activation_level,
-                                       kActivationLevelEnabled))
-    return mojom::ActivationLevel::kEnabled;
-  else if (base::EqualsCaseInsensitiveASCII(activation_level,
-                                            kActivationLevelDryRun))
-    return mojom::ActivationLevel::kDryRun;
-  return mojom::ActivationLevel::kDisabled;
-}
-
-ActivationScope ParseActivationScope(const base::StringPiece activation_scope) {
-  if (base::EqualsCaseInsensitiveASCII(activation_scope,
-                                       kActivationScopeAllSites))
-    return ActivationScope::ALL_SITES;
-  else if (base::EqualsCaseInsensitiveASCII(activation_scope,
-                                            kActivationScopeActivationList))
-    return ActivationScope::ACTIVATION_LIST;
-  return ActivationScope::NO_SITES;
-}
-
-ActivationList ParseActivationList(std::string activation_lists_string) {
-  CommaSeparatedStrings activation_lists(std::move(activation_lists_string));
-  if (activation_lists.CaseInsensitiveContains(
-          kActivationListPhishingInterstitial)) {
-    return ActivationList::PHISHING_INTERSTITIAL;
-  } else if (activation_lists.CaseInsensitiveContains(
-                 kActivationListSocialEngineeringAdsInterstitial)) {
-    return ActivationList::SOCIAL_ENG_ADS_INTERSTITIAL;
-  } else if (activation_lists.CaseInsensitiveContains(
-                 kActivationListSubresourceFilter)) {
-    return ActivationList::SUBRESOURCE_FILTER;
-  } else if (activation_lists.CaseInsensitiveContains(
-                 kActivationListBetterAds)) {
-    return ActivationList::BETTER_ADS;
-  }
-  return ActivationList::NONE;
-}
-
-// Will return a value between 0 and 1 inclusive.
-double ParsePerformanceMeasurementRate(const std::string& rate) {
-  double value = 0.0;
-  if (!base::StringToDouble(rate, &value) || value < 0)
-    return 0.0;
-  return value < 1 ? value : 1;
-}
-
-int ParseInt(const base::StringPiece value) {
-  int result = 0;
-  base::StringToInt(value, &result);
-  return result;
-}
-
-std::vector<Configuration> FillEnabledPresetConfigurations(
-    std::map<std::string, std::string>* params) {
+std::vector<Configuration> FillEnabledPresetConfigurations() {
   // If ad tagging is enabled, turn on the dryrun automatically.
   bool ad_tagging_enabled = base::FeatureList::IsEnabled(kAdTagging);
   const struct {
@@ -127,23 +62,16 @@ std::vector<Configuration> FillEnabledPresetConfigurations(
     bool enabled_by_default;
     Configuration (*factory_method)();
   } kAvailablePresetConfigurations[] = {
-      {kPresetLiveRunOnPhishingSites, true,
+      {kPresetLiveRunOnPhishingSites, false,
        &Configuration::MakePresetForLiveRunOnPhishingSites},
       {kPresetPerformanceTestingDryRunOnAllSites, ad_tagging_enabled,
        &Configuration::MakePresetForPerformanceTestingDryRunOnAllSites},
       {kPresetLiveRunForBetterAds, true,
        &Configuration::MakePresetForLiveRunForBetterAds}};
 
-  CommaSeparatedStrings enabled_presets(
-      TakeVariationParamOrReturnEmpty(params, kEnablePresetsParameterName));
-  CommaSeparatedStrings disabled_presets(
-      TakeVariationParamOrReturnEmpty(params, kDisablePresetsParameterName));
-
   std::vector<Configuration> enabled_configurations;
   for (const auto& available_preset : kAvailablePresetConfigurations) {
-    if ((enabled_presets.CaseInsensitiveContains(available_preset.name) ||
-         available_preset.enabled_by_default) &&
-        !disabled_presets.CaseInsensitiveContains(available_preset.name)) {
+    if (available_preset.enabled_by_default) {
       enabled_configurations.push_back(available_preset.factory_method());
     }
   }
@@ -151,46 +79,10 @@ std::vector<Configuration> FillEnabledPresetConfigurations(
   return enabled_configurations;
 }
 
-Configuration ParseExperimentalConfiguration(
-    std::map<std::string, std::string>* params) {
-  Configuration configuration;
-
-  // ActivationConditions:
-  configuration.activation_conditions.activation_scope = ParseActivationScope(
-      TakeVariationParamOrReturnEmpty(params, kActivationScopeParameterName));
-
-  configuration.activation_conditions.activation_list = ParseActivationList(
-      TakeVariationParamOrReturnEmpty(params, kActivationListsParameterName));
-
-  configuration.activation_conditions.priority =
-      ParseInt(TakeVariationParamOrReturnEmpty(
-          params, kActivationPriorityParameterName));
-
-  // ActivationOptions:
-  configuration.activation_options.activation_level = ParseActivationLevel(
-      TakeVariationParamOrReturnEmpty(params, kActivationLevelParameterName));
-
-  configuration.activation_options.performance_measurement_rate =
-      ParsePerformanceMeasurementRate(TakeVariationParamOrReturnEmpty(
-          params, kPerformanceMeasurementRateParameterName));
-
-  // GeneralSettings:
-  configuration.general_settings.ruleset_flavor =
-      TakeVariationParamOrReturnEmpty(params, kRulesetFlavorParameterName);
-
-  return configuration;
-}
-
 std::vector<Configuration> ParseEnabledConfigurations() {
-  std::map<std::string, std::string> params;
-  base::GetFieldTrialParamsByFeature(kSafeBrowsingSubresourceFilter, &params);
-
   std::vector<Configuration> configs;
   if (base::FeatureList::IsEnabled(kSafeBrowsingSubresourceFilter))
-    configs = FillEnabledPresetConfigurations(&params);
-
-  Configuration experimental_config = ParseExperimentalConfiguration(&params);
-  configs.push_back(std::move(experimental_config));
+    configs = FillEnabledPresetConfigurations();
 
   return configs;
 }
diff --git a/components/subresource_filter/core/common/indexed_ruleset.cc b/components/subresource_filter/core/common/indexed_ruleset.cc
--- a/components/subresource_filter/core/common/indexed_ruleset.cc
+++ b/components/subresource_filter/core/common/indexed_ruleset.cc
@@ -5,6 +5,7 @@
 #include "components/subresource_filter/core/common/indexed_ruleset.h"
 
 #include "base/check.h"
+#include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event.h"
 #include "components/subresource_filter/core/common/first_party_origin.h"
@@ -36,8 +37,10 @@ VerifyStatus GetVerifyStatus(const uint8_t* buffer,
   // least once.  The verifier detects a subset of the errors detected by the
   // checksum, and is unneeded once expected_checksum is consistently nonzero.
   flatbuffers::Verifier verifier(buffer, size);
+  int local_checksum = LocalGetChecksum(buffer, size);
+  LOG(INFO) << "GetVerifyStatus: expected checksum = 0x" << std::hex << expected_checksum << ", local checksum = 0x" << std::hex << local_checksum;
   if (expected_checksum != 0 &&
-      expected_checksum != LocalGetChecksum(buffer, size)) {
+      expected_checksum != local_checksum) {
     return flat::VerifyIndexedRulesetBuffer(verifier)
                ? VerifyStatus::kChecksumFailVerifierPass
                : VerifyStatus::kChecksumFailVerifierFail;
diff --git a/content/browser/renderer_host/navigation_throttle_runner.cc b/content/browser/renderer_host/navigation_throttle_runner.cc
--- a/content/browser/renderer_host/navigation_throttle_runner.cc
+++ b/content/browser/renderer_host/navigation_throttle_runner.cc
@@ -237,11 +237,6 @@ void NavigationThrottleRunner::
   // subframe navigations should not proceed.
   AddThrottle(
       SubframeHistoryNavigationThrottle::MaybeCreateThrottleFor(request));
-
-  // Insert all testing NavigationThrottles last.
-  throttles_.insert(throttles_.end(),
-                    std::make_move_iterator(testing_throttles.begin()),
-                    std::make_move_iterator(testing_throttles.end()));
 }
 
 NavigationThrottle* NavigationThrottleRunner::GetDeferringThrottle() const {
diff --git a/third_party/blink/common/features.cc b/third_party/blink/common/features.cc
--- a/third_party/blink/common/features.cc
+++ b/third_party/blink/common/features.cc
@@ -42,8 +42,8 @@ BASE_FEATURE(kAutofillDetectRemovedFormControls,
 // Apply lazy-loading to ad frames which have embeds likely impacting Core Web
 // Vitals.
 BASE_FEATURE(kAutomaticLazyFrameLoadingToAds,
-             "AutomaticLazyFrameLoadingToAds",
-             base::FEATURE_DISABLED_BY_DEFAULT);
+             "AutomaticLazyFrameLoadingToAds",       // must be enabled
+             base::FEATURE_ENABLED_BY_DEFAULT);      // in Bromite
 
 // The timeout value that forces loading iframes that are lazy loaded by
 // LazyAds. After this timeout, the frame loading is triggered even when the
@@ -63,8 +63,8 @@ const base::FeatureParam<int> kSkipFrameCountForLazyAds(
 // Apply lazy-loading to frames which have embeds likely impacting Core Web
 // Vitals.
 BASE_FEATURE(kAutomaticLazyFrameLoadingToEmbeds,
-             "AutomaticLazyFrameLoadingToEmbeds",
-             base::FEATURE_DISABLED_BY_DEFAULT);
+             "AutomaticLazyFrameLoadingToEmbeds",    // must be enabled
+             base::FEATURE_ENABLED_BY_DEFAULT);      // in Bromite
 
 // The timeout value that forces loading iframes that are lazy loaded by
 // LazyEmbeds. After this timeout, the frame loading is triggered even when the
@@ -86,8 +86,8 @@ const base::FeatureParam<int> kSkipFrameCountForLazyEmbeds(
 // to gather Blink.AutomaticLazyLoadFrame.LazyEmbedFrameCount UKM data even when
 // kAutomaticLazyFrameLoadingToEmbeds is disabled.
 BASE_FEATURE(kAutomaticLazyFrameLoadingToEmbedUrls,
-             "AutomaticLazyFrameLoadingToEmbedUrls",
-             base::FEATURE_DISABLED_BY_DEFAULT);
+             "AutomaticLazyFrameLoadingToEmbedUrls",    // must be disabled
+             base::FEATURE_DISABLED_BY_DEFAULT);        // in Bromite
 
 // Define the strategy for LazyEmbeds to decide which frames we apply
 // lazy-loading or not. If the loading strategy is kAllowList, the detection
-- 
2.40.1