Move LayerSorter to exist locally only in layer_tree_host_common

cc/layer_tree_host_impl.h

 // Copyright 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 CC_LAYER_TREE_HOST_IMPL_H_
 #define CC_LAYER_TREE_HOST_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "cc/animation_events.h"
 #include "cc/cc_export.h"
 #include "cc/input_handler.h"
-#include "cc/layer_sorter.h"
 #include "cc/render_pass.h"
 #include "cc/render_pass_sink.h"
 #include "cc/renderer.h"
 #include "cc/tile_manager.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/rect.h"
 #include <public/WebCompositorOutputSurfaceClient.h>
 
 namespace cc {
 
@@ skipping 333 matching lines @@
     // If this is true, it is necessary to traverse the layer tree ticking the animators.
     bool m_needsAnimateLayers;
     bool m_pinchGestureActive;
     gfx::Point m_previousPinchAnchor;
 
     scoped_ptr<PageScaleAnimation> m_pageScaleAnimation;
 
     // This is used for ticking animations slowly when hidden.
     scoped_ptr<LayerTreeHostImplTimeSourceAdapter> m_timeSourceClientAdapter;
 
-    LayerSorter m_layerSorter;
-
     // List of visible layers for the most recently prepared frame. Used for
     // rendering and input event hit testing.
     LayerList m_renderSurfaceLayerList;
 
     PinchZoomViewport m_pinchZoomViewport;
 
     scoped_ptr<FrameRateCounter> m_fpsCounter;
     scoped_ptr<DebugRectHistory> m_debugRectHistory;
 
     size_t m_numImplThreadScrolls;
     size_t m_numMainThreadScrolls;
 
     size_t m_cumulativeNumLayersDrawn;
 
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_IMPL_H_