Enable disabling WebCore::GraphicsContext in telemetry.

cc/resources/picture_unittest.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 "cc/resources/picture.h"
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "cc/test/fake_content_layer_client.h"
@@ skipping 462 matching lines @@
                             Picture::RECORD_WITH_SK_NULL_CANVAS);
   EXPECT_TRUE(content_layer_client.last_canvas() != NULL);
   EXPECT_TRUE(picture);
 
   picture = Picture::Create(layer_rect,
                             &content_layer_client,
                             tile_grid_info,
                             false,
                             0,
                             Picture::RECORD_WITH_PAINTING_DISABLED);
-  EXPECT_EQ(NULL, content_layer_client.last_canvas());
+  EXPECT_TRUE(content_layer_client.last_canvas() != NULL);

[Sami, 2014/04/29 10:57:23]

Could we also check that content_layer_client was told to disable the graphics
context?

[Stephen Chennney, 2014/04/29 20:30:45]

There is no way to get to the context to ask it if it is disables. We could
maybe check that nothing has been drawn, but that is dangerous as some other
code might draw into the canvas outside of GraphicsContext.

[Sami, 2014/04/29 20:47:48]

I was more thinking of extending cc's FakeContentLayerClient to keep track of
whether it was asked to disable the context or not.

   EXPECT_TRUE(picture);
 
   EXPECT_EQ(3, Picture::RECORDING_MODE_COUNT);
 }
 
 }  // namespace
 }  // namespace cc