cc: Generate tilings at other scales for impl-side painting

cc/picture_layer_tiling.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_PICTURE_LAYER_TILING_H_
 #define CC_PICTURE_LAYER_TILING_H_
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/cc_export.h"
 #include "cc/hash_pair.h"
 #include "cc/region.h"
 #include "cc/tile.h"
+#include "cc/tile_priority.h"
 #include "cc/tiling_data.h"
 #include "ui/gfx/rect.h"
 
 namespace cc {
 
 class PictureLayerTiling;
 
 class PictureLayerTilingClient {
   public:
    virtual scoped_refptr<Tile> CreateTile(PictureLayerTiling*, gfx::Rect) = 0;
 };
 
 class CC_EXPORT PictureLayerTiling {
  public:
   ~PictureLayerTiling();
 
   static scoped_ptr<PictureLayerTiling> Create(float contents_scale,
                                                gfx::Size tile_size);
   scoped_ptr<PictureLayerTiling> Clone() const;
 
   const PictureLayerTiling& operator=(const PictureLayerTiling&);
 
   void SetLayerBounds(gfx::Size layer_bounds);
   void Invalidate(const Region& layer_invalidation);
 
   void SetClient(PictureLayerTilingClient* client);
+  void set_resolution(TileResolution resolution) { resolution_ = resolution; }
 
   gfx::Rect ContentRect() const;
   float contents_scale() const { return contents_scale_; }
 
   // Iterate over all tiles to fill content_rect.  Even if tiles are invalid
   // (i.e. no valid resource) this tiling should still iterate over them.
   // The union of all geometry_rect calls for each element iterated over should
   // exactly equal content_rect and no two geometry_rects should intersect.
   class CC_EXPORT Iterator {
    public:
@@ skipping 31 matching lines @@
     friend class PictureLayerTiling;
   };
 
   Region OpaqueRegionInContentRect(const gfx::Rect&) const;
 
   void Reset() { return tiles_.clear(); }
 
   void UpdateTilePriorities(
       WhichTree tree,
       const gfx::Size& device_viewport,
-      float layer_content_scale_x,
-      float layer_content_scale_y,
+      float last_contents_scale,
+      float current_contents_scale,
       const gfx::Transform& last_screen_transform,
       const gfx::Transform& current_screen_transform,
       double time_delta);
 
  protected:
   typedef std::pair<int, int> TileMapKey;
   typedef base::hash_map<TileMapKey, scoped_refptr<Tile> > TileMap;
 
   PictureLayerTiling(float contents_scale, gfx::Size tileSize);
   Tile* TileAt(int, int) const;
   void CreateTile(int i, int j);
 
   PictureLayerTilingClient* client_;
   float contents_scale_;
   gfx::Size layer_bounds_;
   TileMap tiles_;
   TilingData tiling_data_;
+  TileResolution resolution_;
 
   friend class Iterator;
 };
 
 }  // namespace cc
 
 #endif  // CC_PICTURE_LAYER_TILING_H_