Remove some stray blink::WebGraphicsContext3D references from ui/

ui/compositor/compositor.h

 // Copyright (c) 2012 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_COMPOSITOR_COMPOSITOR_H_
 #define UI_COMPOSITOR_COMPOSITOR_H_
 
 #include <string>
 
 #include "base/containers/hash_tables.h"
@@ skipping 10 matching lines @@
 #include "ui/gfx/size.h"
 #include "ui/gfx/vector2d.h"
 
 class SkBitmap;
 
 namespace base {
 class MessageLoopProxy;
 class RunLoop;
 }
 
-namespace blink {
-class WebGraphicsContext3D;
-}
-
 namespace cc {
 class ContextProvider;
 class Layer;
 class LayerTreeDebugState;
 class LayerTreeHost;
 }
 
 namespace gfx {
 class Rect;
 class Size;
@@ skipping 290 matching lines @@
   bool draw_on_compositing_end_;
 
   base::WeakPtrFactory<Compositor> schedule_draw_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_