Revert of cc: Add occlusion checker as a fixed view of occlusion tracker.

cc/layers/layer_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_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <set>
 #include <string>
 
@@ skipping 31 matching lines @@
 }
 
 class DictionaryValue;
 }
 
 namespace cc {
 
 class LayerTreeHostImpl;
 class LayerTreeImpl;
 class MicroBenchmarkImpl;
-class Occlusion;
 template <typename LayerType>
 class OcclusionTracker;
 class RenderPass;
 class RenderPassId;
 class Renderer;
 class ScrollbarAnimationController;
 class ScrollbarLayerImplBase;
 class SimpleEnclosedRegion;
 class Tile;
 
@@ skipping 135 matching lines @@
                            AppendQuadsData* append_quads_data) {}
   virtual void DidDraw(ResourceProvider* resource_provider);
 
   virtual ResourceProvider::ResourceId ContentsResourceId() const;
 
   virtual bool HasDelegatedContent() const;
   virtual bool HasContributingDelegatedRenderPasses() const;
   virtual RenderPassId FirstContributingRenderPassId() const;
   virtual RenderPassId NextContributingRenderPassId(RenderPassId id) const;
 
-  virtual void UpdateTiles(const Occlusion& occlusion_in_layer_space) {}
+  virtual void UpdateTiles(
+      const OcclusionTracker<LayerImpl>* occlusion_tracker) {}
   virtual void NotifyTileStateChanged(const Tile* tile) {}
 
   virtual ScrollbarLayerImplBase* ToScrollbarLayer();
 
   // Returns true if this layer has content to draw.
   void SetDrawsContent(bool draws_content);
   bool DrawsContent() const { return draws_content_; }
 
   int NumDescendantsThatDrawContent() const;
   void SetHideLayerAndSubtree(bool hide);
@@ skipping 485 matching lines @@
   DrawProperties<LayerImpl> draw_properties_;
 
   scoped_refptr<base::debug::ConvertableToTraceFormat> debug_info_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_