Using experiments to activate the DisplayList2DCanvas optimization

content/child/runtime_features.cc

 // Copyright 2013 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.
 
 #include "content/child/runtime_features.h"
 
 #include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "content/common/content_switches_internal.h"
 #include "content/public/common/content_switches.h"
 #include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "ui/native_theme/native_theme_switches.h"
 
 #if defined(OS_ANDROID)
 #include <cpu-features.h>
 #include "base/android/build_info.h"
 #include "base/metrics/field_trial.h"
 #include "media/base/android/media_codec_bridge.h"
@@ skipping 120 matching lines @@
 
   if (command_line.HasSwitch(switches::kEnableWebMIDI))
     WebRuntimeFeatures::enableWebMIDI(true);
 
   if (command_line.HasSwitch(switches::kDisableFileSystem))
     WebRuntimeFeatures::enableFileSystem(false);
 
   if (command_line.HasSwitch(switches::kEnableExperimentalCanvasFeatures))
     WebRuntimeFeatures::enableExperimentalCanvasFeatures(true);
 
-  if (command_line.HasSwitch(switches::kEnableDisplayList2dCanvas))
+  if (command_line.HasSwitch(switches::kDisableDisplayList2dCanvas)) {
+    WebRuntimeFeatures::enableDisplayList2dCanvas(false);
+  } else if (command_line.HasSwitch(switches::kEnableDisplayList2dCanvas)) {
     WebRuntimeFeatures::enableDisplayList2dCanvas(true);
+  } else {
+    WebRuntimeFeatures::enableDisplayList2dCanvas(
+        base::FieldTrialList::FindFullName("DisplayList2dCanvas") == "Enabled"
+    );
+  }
 
   if (command_line.HasSwitch(switches::kEnableWebGLDraftExtensions))
     WebRuntimeFeatures::enableWebGLDraftExtensions(true);
 
   if (command_line.HasSwitch(switches::kEnableWebGLImageChromium))
     WebRuntimeFeatures::enableWebGLImageChromium(true);
 
   if (command_line.HasSwitch(switches::kEnableOverlayFullscreenVideo))
     WebRuntimeFeatures::enableOverlayFullscreenVideo(true);
 
@@ skipping 13 matching lines @@
     WebRuntimeFeatures::enableLayerSquashing(true);
 
   if (command_line.HasSwitch(switches::kEnableNetworkInformation) ||
       command_line.HasSwitch(
           switches::kEnableExperimentalWebPlatformFeatures)) {
     WebRuntimeFeatures::enableNetworkInformation(true);
   }
 }
 
 }  // namespace content