cc: Do not cleanup tiles with raster tasks.

cc/layers/picture_layer_impl.h

 // Copyright 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 CC_LAYERS_PICTURE_LAYER_IMPL_H_
 #define CC_LAYERS_PICTURE_LAYER_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 105 matching lines @@
     const gfx::Rect& content_rect) OVERRIDE;
   virtual PicturePileImpl* GetPile() OVERRIDE;
   virtual gfx::Size CalculateTileSize(
       const gfx::Size& content_bounds) const OVERRIDE;
   virtual const Region* GetInvalidation() OVERRIDE;
   virtual const PictureLayerTiling* GetTwinTiling(
       const PictureLayerTiling* tiling) const OVERRIDE;
   virtual size_t GetMaxTilesForInterestArea() const OVERRIDE;
   virtual float GetSkewportTargetTimeInSeconds() const OVERRIDE;
   virtual int GetSkewportExtrapolationLimitInContentPixels() const OVERRIDE;
+  virtual WhichTree GetTree() const OVERRIDE;
 
   // PushPropertiesTo active tree => pending tree.
   void SyncTiling(const PictureLayerTiling* tiling);
 
   // Mask-related functions
   void SetIsMask(bool is_mask);
   virtual ResourceProvider::ResourceId ContentsResourceId() const OVERRIDE;
 
   virtual size_t GPUMemoryUsageInBytes() const OVERRIDE;
 
   virtual void RunMicroBenchmark(MicroBenchmarkImpl* benchmark) OVERRIDE;
 
   // Functions used by tile manager.
   PictureLayerImpl* GetTwinLayer() { return twin_layer_; }
-  WhichTree GetTree() const;
   bool IsOnActiveOrPendingTree() const;
   bool HasValidTilePriorities() const;
   bool AllTilesRequiredForActivationAreReadyToDraw() const;
 
  protected:
   friend class LayerRasterTileIterator;
 
   PictureLayerImpl(LayerTreeImpl* tree_impl, int id);
   PictureLayerTiling* AddTiling(float contents_scale);
   void RemoveTiling(float contents_scale);
@@ skipping 66 matching lines @@
   gfx::Size viewport_size_for_tile_priority_;
   gfx::Transform screen_space_transform_for_tile_priority_;
 
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_