Add runtime flag to enable the display list 2D canvas implementation

This change adds the command line switch --enable-display-list-2d-canvas
and adds a corresponding entry to the chrome://flags page

BUG=392594

Review URL: https://codereview.chromium.org/405163004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@285119 0039d316-1c4b-4281-b951-d872f2087c98

chrome/app/generated_resources.grd

@@ -5724,6 +5724,12 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_DISABLE_ACCELERATED_2D_CANVAS_DESCRIPTION" desc="Description of the 'Disable accelerated 2D canvas' lab.">
         Disables the use of the GPU to perform 2d canvas rendering and instead uses software rendering.
       </message>
+      <message name="IDS_FLAGS_ENABLE_DISPLAY_LIST_2D_CANVAS_NAME" desc="Name of the 'Enable display list 2D canvas' lab.">
+        Enable display list 2D canvas
+      </message>
+      <message name="IDS_FLAGS_ENABLE_DISPLAY_LIST_2D_CANVAS_DESCRIPTION" desc="Description of the 'Enable display list 2D canvas' lab.">
+        Enables the use of display lists to record 2D canvas commands. This allows 2D canvas rasterization to be performed on separate thread.
+      </message>
       <message name="IDS_FLAGS_EXPERIMENTAL_EXTENSION_APIS_NAME" desc="Name of the 'Experimental Extension APIs' lab.">
         Experimental Extension APIs
       </message>

chrome/browser/about_flags.cc

@@ -574,6 +574,13 @@ const Experiment kExperiments[] = {
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kDisableAccelerated2dCanvas)
   },
+  {
+    "enable-display-list-2d-canvas",
+    IDS_FLAGS_ENABLE_DISPLAY_LIST_2D_CANVAS_NAME,
+    IDS_FLAGS_ENABLE_DISPLAY_LIST_2D_CANVAS_DESCRIPTION,
+    kOsAll,
+    SINGLE_VALUE_TYPE(switches::kEnableDisplayList2dCanvas)
+  },
   {
     "composited-layer-borders",
     IDS_FLAGS_COMPOSITED_LAYER_BORDERS,

chrome/browser/chromeos/login/chrome_restart_request.cc

@@ -98,6 +98,7 @@ std::string DeriveCommandLine(const GURL& start_url,
     ::switches::kEnableBeginFrameScheduling,
     ::switches::kEnableCompositingForFixedPosition,
     ::switches::kEnableDelegatedRenderer,
+    ::switches::kEnableDisplayList2dCanvas,
     ::switches::kEnableEncryptedMedia,
     ::switches::kEnableFastTextAutosizing,
     ::switches::kDisableGpuSandbox,

content/browser/renderer_host/render_process_host_impl.cc

@@ -1125,6 +1125,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableCompositingForFixedPosition,
     switches::kEnableCompositingForTransition,
     switches::kEnableDeferredImageDecoding,
+    switches::kEnableDisplayList2dCanvas,
     switches::kEnableDistanceFieldText,
     switches::kEnableEncryptedMedia,
     switches::kEnableExperimentalCanvasFeatures,

content/child/runtime_features.cc

@@ -132,6 +132,9 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (command_line.HasSwitch(switches::kEnableSpeechSynthesis))
     WebRuntimeFeatures::enableSpeechSynthesis(true);
 
+  if (command_line.HasSwitch(switches::kEnableDisplayList2dCanvas))
+    WebRuntimeFeatures::enableDisplayList2dCanvas(true);
+
   if (command_line.HasSwitch(switches::kEnableWebGLDraftExtensions))
     WebRuntimeFeatures::enableWebGLDraftExtensions(true);
 

content/public/common/content_switches.cc

@@ -349,6 +349,9 @@ const char kEnableDeferredImageDecoding[]   = "enable-deferred-image-decoding";
 // Enables delegated renderer.
 const char kEnableDelegatedRenderer[]       = "enable-delegated-renderer";
 
+// Enables display list based 2d canvas implementation.
+const char kEnableDisplayList2dCanvas[]     = "enable-display-list-2d-canvas";
+
 // Enables restarting interrupted downloads.
 const char kEnableDownloadResumption[]      = "enable-download-resumption";
 

content/public/common/content_switches.h

@@ -101,6 +101,7 @@ CONTENT_EXPORT extern const char kEnableCompositingForFixedPosition[];
 CONTENT_EXPORT extern const char kEnableCompositingForTransition[];
 CONTENT_EXPORT extern const char kEnableDeferredImageDecoding[];
 CONTENT_EXPORT extern const char kEnableDelegatedRenderer[];
+CONTENT_EXPORT extern const char kEnableDisplayList2dCanvas[];
 CONTENT_EXPORT extern const char kEnableDistanceFieldText[];
 CONTENT_EXPORT extern const char kEnableDownloadResumption[];
 CONTENT_EXPORT extern const char kEnableEncryptedMedia[];