cc: Simplify picture layer tiling update tile priorities.

cc/resources/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_RESOURCES_PICTURE_LAYER_TILING_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 117 matching lines @@
 
     friend class PictureLayerTiling;
   };
 
   Region OpaqueRegionInContentRect(const gfx::Rect& content_rect) const;
 
   void Reset();
 
   void UpdateTilePriorities(
       WhichTree tree,
-      const gfx::Size& device_viewport,
       const gfx::Rect& viewport_in_layer_space,
       const gfx::Rect& visible_layer_rect,
-      const gfx::Size& last_layer_bounds,
-      const gfx::Size& current_layer_bounds,
-      float last_layer_contents_scale,
-      float current_layer_contents_scale,
-      const gfx::Transform& last_screen_transform,
-      const gfx::Transform& current_screen_transform,
+      float layer_contents_scale,
       double current_frame_time_in_seconds,
       size_t max_tiles_for_interest_area);

[enne (OOO), 2014/01/31 23:07:46]

This isn't part of your patch, but we don't change this at runtime in practice,
right? Could this be a constructor or other setter parameter?

(I'm happy with how few parameters get passed to this function and so I'm
itching to remove even more.)

[vmpstr, 2014/02/03 20:27:24]

Done. But to avoid passing this in other functions that create a tiling, I made
this a getter on the client. Personally, I like that better, but let me know.

 
   // Copies the src_tree priority into the dst_tree priority for all tiles.
   // The src_tree priority is reset to the lowest priority possible.  This
   // also updates the pile on each tile to be the current client's pile.
   void DidBecomeActive();
 
   // Resets the active priority for all tiles in a tiling, when an active
   // tiling is becoming recycled. This may include some tiles which are
   // not in the the pending tiling (due to invalidations). This must
   // be called before DidBecomeActive, as it resets the active priority
@@ skipping 32 matching lines @@
  protected:
   typedef std::pair<int, int> TileMapKey;
   typedef base::hash_map<TileMapKey, scoped_refptr<Tile> > TileMap;
 
   PictureLayerTiling(float contents_scale,
                      const gfx::Size& layer_bounds,
                      PictureLayerTilingClient* client);
   void SetLiveTilesRect(const gfx::Rect& live_tiles_rect);
   void CreateTile(int i, int j, const PictureLayerTiling* twin_tiling);
 
+  gfx::Rect ComputeVisibleRect(const gfx::Rect& viewport_in_layer_space,
+                               const gfx::Rect& visible_layer_rect) const;
+
+  gfx::Rect ComputeSkewport(double current_frame_time_in_seconds,
+                            const gfx::Rect& visible_rect_in_content_space)
+      const;
+
   // Given properties.
   float contents_scale_;
   gfx::Size layer_bounds_;
   TileResolution resolution_;
   PictureLayerTilingClient* client_;
 
   // Internal data.
   TilingData tiling_data_;
   TileMap tiles_;  // It is not legal to have a NULL tile in the tiles_ map.
   gfx::Rect live_tiles_rect_;
 
   // State saved for computing velocities based upon finite differences.
   double last_impl_frame_time_in_seconds_;
+  gfx::RectF last_visible_rect_in_content_space_;
 
   friend class CoverageIterator;
 
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 
   RectExpansionCache expansion_cache_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_