Add chromium and blink flags for never-slow-mode.

- This is the first step in implementing never-slow-mode in chrome.
- Both flags are disabled by default.
- Blink runtime flag will use the chromium feature state.

Bug: 892672
Change-Id: I2098e435628219ffe5a798d485d73e1e0c590bc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864331Reviewed-by: Jason Chase <chasej@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Rodney Ding <rodneyding@google.com>
Cr-Commit-Position: refs/heads/master@{#707482}

content/child/runtime_features.cc

@@ -310,6 +310,8 @@ void SetRuntimeFeaturesFromChromiumFeatures() {
            kEnableOnly},
           {wf::EnableDocumentPolicy, features::kDocumentPolicy,
            kUseFeatureState},
+          {wf::EnableNeverSlowMode, features::kNeverSlowMode,
+           kUseFeatureState},
       };
   for (const auto& mapping : blinkFeatureToBaseFeatureMapping) {
     const bool featureEnabled =

content/public/common/content_features.cc

@@ -318,6 +318,9 @@ const base::Feature kNetworkServiceInProcess {
 #endif
 };
 
+const base::Feature kNeverSlowMode{"NeverSlowMode",
+                                   base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Kill switch for Web Notification content images.
 const base::Feature kNotificationContentImage{"NotificationContentImage",
                                               base::FEATURE_ENABLED_BY_DEFAULT};

content/public/common/content_features.h

@@ -75,6 +75,7 @@ CONTENT_EXPORT extern const base::Feature kMouseSubframeNoImplicitCapture;
 CONTENT_EXPORT extern const base::Feature kNavigationImmediateResponseBody;
 CONTENT_EXPORT extern const base::Feature kNetworkQualityEstimatorWebHoldback;
 CONTENT_EXPORT extern const base::Feature kNetworkServiceInProcess;
+CONTENT_EXPORT extern const base::Feature kNeverSlowMode;
 CONTENT_EXPORT extern const base::Feature kNotificationContentImage;
 CONTENT_EXPORT extern const base::Feature kNotificationTriggers;
 CONTENT_EXPORT extern const base::Feature kOriginPolicy;

third_party/blink/public/platform/web_runtime_features.h

@@ -127,6 +127,7 @@ class WebRuntimeFeatures {
       bool);
   BLINK_PLATFORM_EXPORT static void EnableNavigatorContentUtils(bool);
   BLINK_PLATFORM_EXPORT static void EnableNetInfoDownlinkMax(bool);
+  BLINK_PLATFORM_EXPORT static void EnableNeverSlowMode(bool);
   BLINK_PLATFORM_EXPORT static void EnableUpdateHoverAtBeginFrame(bool);
   BLINK_PLATFORM_EXPORT static void EnableNotificationConstructor(bool);
   BLINK_PLATFORM_EXPORT static void EnableNotificationContentImage(bool);

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

@@ -292,6 +292,10 @@ void WebRuntimeFeatures::EnableNetInfoDownlinkMax(bool enable) {
   RuntimeEnabledFeatures::SetNetInfoDownlinkMaxEnabled(enable);
 }
 
+void WebRuntimeFeatures::EnableNeverSlowMode(bool enable) {
+  RuntimeEnabledFeatures::SetNeverSlowModeEnabled(enable);
+}
+
 void WebRuntimeFeatures::EnableOnDeviceChange(bool enable) {
   RuntimeEnabledFeatures::SetOnDeviceChangeEnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1083,6 +1083,9 @@
       // Only Android, ChromeOS support NetInfo downlinkMax, type and ontypechange now
       status: {"Android": "stable", "ChromeOS": "stable"},
     },
+    {
+      name: "NeverSlowMode",
+    },
     // Not a web exposed feature, enabled from the command line.
     {
       name: "NewRemotePlaybackPipeline",