cc: Replace Region with SimpleEnclosedRegion for occlusion tracking

cc/layers/tiled_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_TILED_LAYER_IMPL_H_
 #define CC_LAYERS_TILED_LAYER_IMPL_H_
 
 #include <string>
 
 #include "cc/base/cc_export.h"
@@ skipping 25 matching lines @@
 
   void set_skips_draw(bool skips_draw) { skips_draw_ = skips_draw; }
   void SetTilingData(const LayerTilingData& tiler);
   void PushTileProperties(int i,
                           int j,
                           ResourceProvider::ResourceId resource,
                           const gfx::Rect& opaque_rect,
                           bool contents_swizzled);
   void PushInvalidTile(int i, int j);
 
-  virtual Region VisibleContentOpaqueRegion() const OVERRIDE;
+  virtual SimpleEnclosedRegion VisibleContentOpaqueRegion() const OVERRIDE;
   virtual void ReleaseResources() OVERRIDE;
 
   const LayerTilingData* TilingForTesting() const { return tiler_.get(); }
 
   virtual size_t GPUMemoryUsageInBytes() const OVERRIDE;
 
  protected:
   TiledLayerImpl(LayerTreeImpl* tree_impl, int id);
   // Exposed for testing.
   bool HasTileAt(int i, int j) const;
@@ skipping 12 matching lines @@
   bool skips_draw_;
 
   scoped_ptr<LayerTilingData> tiler_;
 
   DISALLOW_COPY_AND_ASSIGN(TiledLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_TILED_LAYER_IMPL_H_