Add two pixel-based compositor unittests.

ui/gfx/compositor/test_compositor.h

-// Copyright (c) 2011 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.
-
-#ifndef UI_GFX_COMPOSITOR_TEST_COMPOSITOR_H_
-#define UI_GFX_COMPOSITOR_TEST_COMPOSITOR_H_
-#pragma once
-
-#include "base/basictypes.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/compiler_specific.h"
-#include "ui/gfx/compositor/compositor.h"
-
-namespace ui {
-
-class TestCompositorDelegate;
-
-// Trivial Compositor implementation that creates Textures of type TestTexture.
-class TestCompositor : public ui::Compositor {
- public:
-  explicit TestCompositor(CompositorDelegate* owner);
-  virtual ~TestCompositor();
-
-  // ui::Compositor:
-  virtual ui::Texture* CreateTexture() OVERRIDE;
-  virtual void OnNotifyStart(bool clear) OVERRIDE;
-  virtual void OnNotifyEnd() OVERRIDE;
-  virtual void Blur(const gfx::Rect& bounds) OVERRIDE;
-  virtual void DrawTree() OVERRIDE;
-  virtual bool ReadPixels(SkBitmap* bitmap) OVERRIDE;
-
-  // A simple factory that creates a test compositor with a given delegate
-  static ui::Compositor* Create(ui::CompositorDelegate* owner);
-
- protected:
-  virtual void OnWidgetSizeChanged() OVERRIDE;
-
- private:
-  scoped_ptr<TestCompositorDelegate> owned_delegate_;
-
-  DISALLOW_COPY_AND_ASSIGN(TestCompositor);
-};
-
-}  // namespace ui
-
-#endif  // UI_GFX_COMPOSITOR_TEST_COMPOSITOR_H_