Enable Canvas2D hardware acceleration for Android WebView

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
===================================================================
--- cc/resources/resource_provider.cc	(revision 243070)
+++ cc/resources/resource_provider.cc	(working copy)
@@ -545,7 +545,7 @@
   }
   if (resource->mailbox.IsValid() && resource->external) {
     GLuint sync_point = resource->mailbox.sync_point();
-    if (resource->mailbox.IsTexture()) {
+    if (resource->mailbox.IsTexture() && ContextGL() != NULL) {

[boliu, 2014/01/06 18:16:13]

I know I did the same thing in my hack patch, but it is just a hack. We are
leaking resource handles if the context is destroyed but there are still gl
resources left.

       lost_resource |= lost_output_surface_;
       GLES2Interface* gl = ContextGL();
       DCHECK(gl);