cc: Replace Region with SimpleEnclosedRegion for occlusion tracking

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 37 matching lines @@
 namespace cc {
 
 class LayerTreeHostImpl;
 class LayerTreeImpl;
 class MicroBenchmarkImpl;
 template <typename LayerType>
 class OcclusionTracker;
 class Renderer;
 class ScrollbarAnimationController;
 class ScrollbarLayerImplBase;
+class SimpleEnclosedRegion;
 class Tile;
 
 struct AppendQuadsData;
 
 enum DrawMode {
   DRAW_MODE_NONE,
   DRAW_MODE_HARDWARE,
   DRAW_MODE_SOFTWARE,
   DRAW_MODE_RESOURCELESS_SOFTWARE
 };
@@ skipping 417 matching lines @@
   void ResetAllChangeTrackingForSubtree();
 
   LayerAnimationController* layer_animation_controller() {
     return layer_animation_controller_.get();
   }
 
   const LayerAnimationController* layer_animation_controller() const {
     return layer_animation_controller_.get();
   }
 
-  virtual Region VisibleContentOpaqueRegion() const;
+  virtual SimpleEnclosedRegion VisibleContentOpaqueRegion() const;
 
   virtual void DidBecomeActive();
 
   virtual void DidBeginTracing();
 
   // Release resources held by this layer. Called when the output surface
   // that rendered this layer was lost or a rendering mode switch has occured.
   virtual void ReleaseResources();
 
   ScrollbarAnimationController* scrollbar_animation_controller() const {
@@ skipping 198 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_