First pass at removal of unneeded dependencies on skia\ext\platform_canvas.h

ui/gfx/canvas.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_CANVAS_H_
 #define UI_GFX_CANVAS_H_
 #pragma once
 
 #include <string>
 
 #include "base/string16.h"
-// TODO(beng): remove this include when we no longer depend on SkTypes.
-#include "skia/ext/platform_canvas.h"
+// TODO(beng): remove these includes when we no longer depend on SkTypes.
+#include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/ui_api.h"
 
 namespace ui {
 class Transform;
 
 typedef unsigned int TextureID;
 }
 
 namespace gfx {
@@ skipping 220 matching lines @@
   // Returns the rectangle that is invalid.
   virtual gfx::Rect GetInvalidRect() const = 0;
 
   // Returns the underlying Canvas.
   virtual Canvas* AsCanvas() = 0;
 };
 
 }  // namespace gfx;
 
 #endif  // UI_GFX_CANVAS_H_