From: Wengling Chen <feiyu2817@gmail.com>
Date: Mon, 1 Feb 2021 19:18:55 +0200
Subject: Add flag for save-data-header

License: GPL-3.0-only - https://spdx.org/licenses/GPL-3.0-only.html
---
 chrome/browser/about_flags.cc                             | 5 ++++-
 chrome/browser/flag_descriptions.cc                       | 4 ++++
 chrome/browser/flag_descriptions.h                        | 3 +++
 .../browser/loader/browser_initiated_resource_request.cc  | 8 ++++++++
 services/network/public/cpp/features.cc                   | 5 +++++
 services/network/public/cpp/features.h                    | 2 ++
 6 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -5597,7 +5597,10 @@ const FeatureEntry kFeatureEntries[] = {
     {"force-text-direction", flag_descriptions::kForceTextDirectionName,
      flag_descriptions::kForceTextDirectionDescription, kOsAll,
      MULTI_VALUE_TYPE(kForceTextDirectionChoices)},
-#if BUILDFLAG(IS_ANDROID)
+#if BUILDFLAG(IS_ANDROID) // Bromite save data header
+    {"enable-save-data-header", flag_descriptions::kEnableSaveDataHeaderName,
+     flag_descriptions::kEnableSaveDataHeaderDescription, kOsAndroid,
+     FEATURE_VALUE_TYPE(network::features::kEnableSaveDataHeader)},
     {"force-update-menu-type", flag_descriptions::kUpdateMenuTypeName,
      flag_descriptions::kUpdateMenuTypeDescription, kOsAndroid,
      MULTI_VALUE_TYPE(kForceUpdateMenuTypeChoices)},
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -1401,6 +1401,10 @@ const char kDeprecateAltBasedSixPackDescription[] =
     "Show deprecation notifications and disable functionality for Alt based "
     "six pack deprecations. The Search based versions continue to work.";
 
+const char kEnableSaveDataHeaderName[] = "Enable save-data header";
+const char kEnableSaveDataHeaderDescription[] =
+    "Enable save-data header without enabling Data Saver.";
+
 const char kDeprecateOldKeyboardShortcutsAcceleratorName[] =
     "Enable deprecation notifications for Ctrl+Alt+/ to open Keyboard "
     "shortcuts app";
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -726,6 +726,9 @@ extern const char kDeprecateAltBasedSixPackDescription[];
 extern const char kDeprecateOldKeyboardShortcutsAcceleratorName[];
 extern const char kDeprecateOldKeyboardShortcutsAcceleratorDescription[];
 
+extern const char kEnableSaveDataHeaderName[];
+extern const char kEnableSaveDataHeaderDescription[];
+
 extern const char kMemlogName[];
 extern const char kMemlogDescription[];
 extern const char kMemlogModeMinimal[];
diff --git a/content/browser/loader/browser_initiated_resource_request.cc b/content/browser/loader/browser_initiated_resource_request.cc
--- a/content/browser/loader/browser_initiated_resource_request.cc
+++ b/content/browser/loader/browser_initiated_resource_request.cc
@@ -4,6 +4,9 @@
 
 #include "content/browser/loader/browser_initiated_resource_request.h"
 
+#include "base/feature_list.h"
+#include "services/network/public/cpp/features.h"
+
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
@@ -37,8 +40,13 @@ void UpdateAdditionalHeadersForBrowserInitiatedRequest(
   // Save-Data was previously included in hints for workers, thus we cannot
   // remove it for the time being. If you're reading this, consider building
   // permissions policies for workers and/or deprecating this inclusion.
+  bool setHeader = false;
   if (is_for_worker_script &&
       GetContentClient()->browser()->IsDataSaverEnabled(browser_context)) {
+    setHeader = true;
+  }
+  setHeader |= base::FeatureList::IsEnabled(network::features::kEnableSaveDataHeader);
+  if (setHeader) {
     if (should_update_existing_headers) {
       headers->RemoveHeader("Save-Data");
     }
diff --git a/services/network/public/cpp/features.cc b/services/network/public/cpp/features.cc
--- a/services/network/public/cpp/features.cc
+++ b/services/network/public/cpp/features.cc
@@ -14,6 +14,11 @@
 
 namespace network::features {
 
+// Enable save-data header separately (without enabled data reduction service).
+BASE_FEATURE(kEnableSaveDataHeader,
+             "EnableSaveDataHeader",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+
 BASE_FEATURE(kNetworkErrorLogging,
              "NetworkErrorLogging",              // disabled by default
              base::FEATURE_DISABLED_BY_DEFAULT); // in bromite
diff --git a/services/network/public/cpp/features.h b/services/network/public/cpp/features.h
--- a/services/network/public/cpp/features.h
+++ b/services/network/public/cpp/features.h
@@ -91,6 +91,8 @@ extern uint32_t GetLoaderChunkSize();
 COMPONENT_EXPORT(NETWORK_CPP)
 BASE_DECLARE_FEATURE(kCorsNonWildcardRequestHeadersSupport);
 
+COMPONENT_EXPORT(NETWORK_CPP) BASE_DECLARE_FEATURE(kEnableSaveDataHeader);
+
 COMPONENT_EXPORT(NETWORK_CPP) BASE_DECLARE_FEATURE(kNetworkServiceMemoryCache);
 
 COMPONENT_EXPORT(NETWORK_CPP) BASE_DECLARE_FEATURE(kOmitCorsClientCert);
--
2.25.1