Add two pixel-based compositor unittests.

ui/gfx/compositor/test_compositor_host.h

Index: ui/gfx/compositor/test_compositor_host.h
diff --git a/ui/gfx/compositor/test_compositor_host.h b/ui/gfx/compositor/test_compositor_host.h
deleted file mode 100644
index 3754aab7ee70b79d4330f0b54da25304246aa552..0000000000000000000000000000000000000000
--- a/ui/gfx/compositor/test_compositor_host.h
+++ /dev/null
@@ -1,34 +0,0 @@
-// 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_HOST_H_
-#define UI_GFX_COMPOSITOR_TEST_COMPOSITOR_HOST_H_
-#pragma once
-
-#include "base/message_loop.h"
-
-namespace gfx {
-class Rect;
-}
-
-namespace ui {
-
-class Compositor;
-
-class TestCompositorHost : public MessageLoop::Dispatcher {
- public:
-  virtual ~TestCompositorHost() {}
-
-  // Creates a new TestCompositorHost. The caller owns the returned value.
-  static TestCompositorHost* Create(const gfx::Rect& bounds);
-
-  // Shows the TestCompositorHost.
-  virtual void Show() = 0;
-
-  virtual ui::Compositor* GetCompositor() = 0;
-};
-
-}  // namespace ui
-
-#endif  // UI_GFX_COMPOSITOR_TEST_COMPOSITOR_HOST_H_