[Background Fetch] Add feature flag for access to

active background fetches.
This allows iterative implementation of this feature.

Bug: 875201
Change-Id: Ia349eb55e682cf22825b53559c8e1f603d189501
Reviewed-on: https://chromium-review.googlesource.com/c/1331397Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Commit-Queue: Mugdha Lakhani <nator@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607537}

content/child/runtime_features.cc

@@ -496,6 +496,10 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (!base::FeatureList::IsEnabled(features::kBackgroundFetch))
     WebRuntimeFeatures::EnableBackgroundFetch(false);
 
+  WebRuntimeFeatures::EnableBackgroundFetchAccessActiveFetches(
+      base::FeatureList::IsEnabled(
+          features::kBackgroundFetchAccessActiveFetches));
+
   WebRuntimeFeatures::EnableBackgroundFetchUploads(
       base::FeatureList::IsEnabled(features::kBackgroundFetchUploads));
 

content/public/common/content_features.cc

@@ -53,6 +53,10 @@ const base::Feature kAwaitOptimization{"AwaitOptimization",
 const base::Feature kBackgroundFetch{"BackgroundFetch",
                                      base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Enables access to active background fetches.
+const base::Feature kBackgroundFetchAccessActiveFetches{
+    "BackgroundFetchAccessActiveFetches", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables using uploads in a Background Fetch.
 const base::Feature kBackgroundFetchUploads{"BackgroundFetchUploads",
                                             base::FEATURE_DISABLED_BY_DEFAULT};

content/public/common/content_features.h

@@ -26,6 +26,7 @@ CONTENT_EXPORT extern const base::Feature kAudioServiceLaunchOnStartup;
 CONTENT_EXPORT extern const base::Feature kAudioServiceOutOfProcess;
 CONTENT_EXPORT extern const base::Feature kAwaitOptimization;
 CONTENT_EXPORT extern const base::Feature kBackgroundFetch;
+CONTENT_EXPORT extern const base::Feature kBackgroundFetchAccessActiveFetches;
 CONTENT_EXPORT extern const base::Feature kBackgroundFetchUploads;
 CONTENT_EXPORT extern const base::Feature kBlinkHeapIncrementalMarking;
 CONTENT_EXPORT extern const base::Feature kBlinkHeapUnifiedGarbageCollection;

third_party/blink/public/platform/web_runtime_features.h

@@ -82,6 +82,8 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnableAllowActivationDelegationAttr(bool);
   BLINK_PLATFORM_EXPORT static void EnableAudioOutputDevices(bool);
   BLINK_PLATFORM_EXPORT static void EnableBackgroundFetch(bool);
+  BLINK_PLATFORM_EXPORT static void EnableBackgroundFetchAccessActiveFetches(
+      bool);
   BLINK_PLATFORM_EXPORT static void EnableBackgroundFetchUploads(bool);
   BLINK_PLATFORM_EXPORT static void EnableBlinkHeapIncrementalMarking(bool);
   BLINK_PLATFORM_EXPORT static void EnableBlinkHeapUnifiedGarbageCollection(

third_party/blink/renderer/modules/background_fetch/background_fetch_registration.cc

@@ -181,7 +181,8 @@ ScriptPromise BackgroundFetchRegistration::MatchImpl(
     bool match_all) {
   // TODO(crbug.com/875201): Update this check once we support access to active
   // fetches.
-  if (result_ == mojom::BackgroundFetchResult::UNSET) {
+  if (result_ == mojom::BackgroundFetchResult::UNSET &&
+      !RuntimeEnabledFeatures::BackgroundFetchAccessActiveFetchesEnabled()) {
     return ScriptPromise::RejectWithDOMException(
         script_state,
         DOMException::Create(

third_party/blink/renderer/platform/exported/web_runtime_features.cc

@@ -568,6 +568,10 @@ void WebRuntimeFeatures::EnableBackgroundFetch(bool enable) {
   RuntimeEnabledFeatures::SetBackgroundFetchEnabled(enable);
 }
 
+void WebRuntimeFeatures::EnableBackgroundFetchAccessActiveFetches(bool enable) {
+  RuntimeEnabledFeatures::SetBackgroundFetchAccessActiveFetchesEnabled(enable);
+}
+
 void WebRuntimeFeatures::EnableBackgroundFetchUploads(bool enable) {
   RuntimeEnabledFeatures::SetBackgroundFetchUploadsEnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -117,6 +117,10 @@
       origin_trial_feature_name: "BackgroundFetch",
       status: "experimental",
     },
+    {
+      name: "BackgroundFetchAccessActiveFetches",
+      status: "experimental",
+    },
     {
       name: "BackgroundFetchUploads",
       status: "experimental",