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

---
 chrome/browser/about_flags.cc                                | 3 +++
 chrome/browser/flag_descriptions.cc                          | 4 ++++
 chrome/browser/flag_descriptions.h                           | 3 +++
 content/browser/loader/browser_initiated_resource_request.cc | 5 +++--
 services/network/public/cpp/features.cc                      | 4 ++++
 services/network/public/cpp/features.h                       | 2 ++
 6 files changed, 19 insertions(+), 2 deletions(-)

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
@@ -4471,6 +4471,9 @@ const FeatureEntry kFeatureEntries[] = {
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 #if defined(OS_ANDROID)
+    {"enable-save-data-header", flag_descriptions::kEnableSaveDataHeaderName,
+     flag_descriptions::kEnableSaveDataHeaderDescription, kOsAndroid,
+     FEATURE_VALUE_TYPE(network::features::kEnableSaveDataHeader)},
     {"enable-command-line-on-non-rooted-devices",
      flag_descriptions::kEnableCommandLineOnNonRootedName,
      flag_descriptions::kEnableCommandLineOnNoRootedDescription, kOsAndroid,
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
@@ -975,6 +975,10 @@ const char kDisableKeepaliveFetchDescription[] =
     "Disable fetch with keepalive set "
     "(https://fetch.spec.whatwg.org/#request-keepalive-flag).";
 
+const char kEnableSaveDataHeaderName[] = "Enable save-data header";
+const char kEnableSaveDataHeaderDescription[] =
+    "Enable save-data header without enabling Data Saver.";
+
 const char kExperimentalAccessibilityLanguageDetectionName[] =
     "Experimental accessibility language detection";
 const char kExperimentalAccessibilityLanguageDetectionDescription[] =
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
@@ -557,6 +557,9 @@ extern const char kDiagnosticsAppDescription[];
 extern const char kDisableKeepaliveFetchName[];
 extern const char kDisableKeepaliveFetchDescription[];
 
+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
@@ -40,9 +40,10 @@ void UpdateAdditionalHeadersForBrowserInitiatedRequest(
 
   // Set the Save-Data header if appropriate.
   // https://tools.ietf.org/html/draft-grigorik-http-client-hints-03#section-7
-  if (GetContentClient()->browser()->IsDataSaverEnabled(browser_context) &&
+  if ((GetContentClient()->browser()->IsDataSaverEnabled(browser_context) &&
       !base::GetFieldTrialParamByFeatureAsBool(features::kDataSaverHoldback,
-                                               "holdback_web", false)) {
+                                               "holdback_web", false)) ||
+      base::FeatureList::IsEnabled(network::features::kEnableSaveDataHeader)) {
     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
@@ -149,6 +149,10 @@ const base::FeatureParam<std::string>
 const base::Feature kDisableKeepaliveFetch{"DisableKeepaliveFetch",
                                            base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enable save-data header seprately, without enabled data reduction service
+const base::Feature kEnableSaveDataHeader{"EnableSaveDataHeader",
+                                           base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Controls whether a |request_initiator| that mismatches
 // |request_initiator_origin_lock| leads to 1) failing the HTTP request and 2)
 // calling mojo::ReportBadMessage (on desktop platforms, where NetworkService
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
@@ -58,6 +58,8 @@ extern const base::FeatureParam<std::string>
 COMPONENT_EXPORT(NETWORK_CPP)
 extern const base::Feature kDisableKeepaliveFetch;
 COMPONENT_EXPORT(NETWORK_CPP)
+extern const base::Feature kEnableSaveDataHeader;
+COMPONENT_EXPORT(NETWORK_CPP)
 extern const base::Feature kRequestInitiatorSiteLockEnfocement;
 
 COMPONENT_EXPORT(NETWORK_CPP)
-- 
2.17.1