cc: Consider visible rect for update tile priority early out.

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 <set>
 #include <utility>
 #include <vector>
@@ skipping 236 matching lines @@
   // 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
   // while DidBecomeActive promotes pending priority on a similar set of tiles.
   void DidBecomeRecycled();
 
-  bool NeedsUpdateForFrameAtTime(double frame_time_in_seconds) {
-    return frame_time_in_seconds != last_impl_frame_time_in_seconds_;
+  bool NeedsUpdateForFrameAtTimeAndViewport(
+      double frame_time_in_seconds,
+      const gfx::Rect& viewport_in_layer_space) {
+    return frame_time_in_seconds != last_impl_frame_time_in_seconds_ ||
+           viewport_in_layer_space != last_viewport_in_layer_space_;
   }
 
   void GetAllTilesForTracing(std::set<const Tile*>* tiles) const;
   void AsValueInto(base::debug::TracedValue* array) const;
   size_t GPUMemoryUsageInBytes() const;
 
   struct RectExpansionCache {
     RectExpansionCache();
 
     gfx::Rect previous_start;
@@ skipping 53 matching lines @@
   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::Rect last_viewport_in_layer_space_;
   gfx::Rect last_visible_rect_in_content_space_;
 
   // Iteration rects in content space
   gfx::Rect current_visible_rect_;
   gfx::Rect current_skewport_rect_;
   gfx::Rect current_soon_border_rect_;
   gfx::Rect current_eventually_rect_;
 
   bool has_visible_rect_tiles_;
   bool has_skewport_rect_tiles_;
@@ skipping 15 matching lines @@
 
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 
   RectExpansionCache expansion_cache_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_