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

content/child/runtime_features.cc

Index: content/child/runtime_features.cc
diff --git a/content/child/runtime_features.cc b/content/child/runtime_features.cc
index bcdc8c72e732422de7578ed4b4075c45e91ea5bf..4f98ca2645da5cee17bdac813f960752fbf0c59b 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -126,6 +126,9 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (command_line.HasSwitch(switches::kEnableSpeechSynthesis))
     WebRuntimeFeatures::enableSpeechSynthesis(true);
 
+  if (command_line.HasSwitch(switches::kEnableDisplayList2dCanvas))

[piman, 2014/07/21 21:45:56]

This will require you to forward the switch to the renderer (see
RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer).

What is the relationship between the WebRuntimeFeatures flag and the
WebPreferences flag? e.g. if one is set but not the other one? If they need to
match, can we add a check?

[Justin Novosad, 2014/07/23 18:56:18]

Done.

+    WebRuntimeFeatures::enableDisplayList2dCanvas(true);
+
   if (command_line.HasSwitch(switches::kEnableWebGLDraftExtensions))
     WebRuntimeFeatures::enableWebGLDraftExtensions(true);