cc: Change preraster/predecode split to be half of max skewport extent.

cc/tiles/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_TILES_PICTURE_LAYER_TILING_H_
 #define CC_TILES_PICTURE_LAYER_TILING_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 65 matching lines @@
   }
 };
 
 class CC_EXPORT PictureLayerTiling {
  public:
   static const int kBorderTexels = 1;
 
   PictureLayerTiling(WhichTree tree,
                      float contents_scale,
                      scoped_refptr<RasterSource> raster_source,
-                     PictureLayerTilingClient* client);
+                     PictureLayerTilingClient* client,
+                     float min_preraster_distance,
+                     float max_preraster_distance);
   ~PictureLayerTiling();
 
   PictureLayerTilingClient* client() const { return client_; }
 
   void SetRasterSourceAndResize(scoped_refptr<RasterSource> raster_source);
   void Invalidate(const Region& layer_invalidation);
   void CreateMissingTilesInLiveTilesRect();
   void TakeTilesAndPropertiesFrom(PictureLayerTiling* pending_twin,
                                   const Region& layer_invalidation);
 
@@ skipping 220 matching lines @@
   const gfx::Rect& current_eventually_rect() const {
     return current_eventually_rect_;
   }
   void RemoveTilesInRegion(const Region& layer_region, bool recreate_tiles);
 
   // Given properties.
   const float contents_scale_;
   PictureLayerTilingClient* const client_;
   const WhichTree tree_;
   scoped_refptr<RasterSource> raster_source_;
+  const float min_preraster_distance_;
+  const float max_preraster_distance_;
   TileResolution resolution_;
   bool may_contain_low_resolution_tiles_;
 
   // 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_;
 
   bool can_require_tiles_for_activation_;
 
   // 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_;
   // Other properties used for tile iteration and prioritization.
   float current_content_to_screen_scale_;
   Occlusion current_occlusion_in_layer_space_;
+  float max_skewport_extent_in_screen_space_;
 
   bool has_visible_rect_tiles_;
   bool has_skewport_rect_tiles_;
   bool has_soon_border_rect_tiles_;
   bool has_eventually_rect_tiles_;
   bool all_tiles_done_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PictureLayerTiling);
 };
 
 }  // namespace cc
 
 #endif  // CC_TILES_PICTURE_LAYER_TILING_H_