cc: Made image comparison for pixel tests error tolerant.

cc/test/pixel_test.h

 // 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 "base/file_util.h"
+#include "cc/test/pixel_comparator.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/size.h"
 
 #ifndef CC_TEST_PIXEL_TEST_H_
 #define CC_TEST_PIXEL_TEST_H_
 
 namespace cc {
 class GLRenderer;
 class OutputSurface;
 class ResourceProvider;
 
 class PixelTest : public testing::Test {
  protected:
   PixelTest();
   virtual ~PixelTest();
 
   virtual void SetUp() OVERRIDE;
 
   bool PixelsMatchReference(const base::FilePath& ref_file,
-      bool discard_transparency);
+                            const PixelComparator& comparator);
 
   gfx::Size device_viewport_size_;
   scoped_ptr<OutputSurface> output_surface_;
   scoped_ptr<ResourceProvider> resource_provider_;
   class PixelTestRendererClient;
   scoped_ptr<PixelTestRendererClient> fake_client_;
   scoped_ptr<GLRenderer> renderer_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_PIXEL_TEST_H_