cc: Low quality support for low res tiles

cc/resources/managed_tile_state.h

 // Copyright 2013 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_MANAGED_TILE_STATE_H_
 #define CC_RESOURCES_MANAGED_TILE_STATE_H_
 
+#include <map>
+
 #include "base/memory/scoped_ptr.h"
 #include "cc/resources/platform_color.h"
 #include "cc/resources/raster_worker_pool.h"
 #include "cc/resources/resource_pool.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/tile_manager.h"
 
 namespace cc {
 
 // This is state that is specific to a tile that is
@@ skipping 50 matching lines @@
 
       void SetResourceForTesting(scoped_ptr<ResourcePool::Resource> resource) {
         resource_ = resource.Pass();
         resource_id_ = resource_->id();
       }
 
       scoped_ptr<ResourcePool::Resource>& GetResourceForTesting() {
         return resource_;
       }
 
+      bool ShouldBeUpdatedBy(TileRasterMode new_mode) const;
+
     private:
       friend class TileManager;
       friend class Tile;
       friend class ManagedTileState;
 
       void set_use_resource() {
         mode_ = RESOURCE_MODE;
       }
 
       void set_solid_color(const SkColor& color) {
         mode_ = SOLID_COLOR_MODE;
         solid_color_ = color;
         resource_id_ = 0;
       }
 
       void set_rasterize_on_demand() {
         mode_ = PICTURE_PILE_MODE;
         resource_id_ = 0;
       }
 
+      void PushPropertiesTo(TileVersion* destination);
+
       Mode mode_;
       SkColor solid_color_;
 
       // TODO(reveman): Eliminate the need for both |resource_id_|
       // and |resource| by re-factoring the "force upload"
       // mechanism. crbug.com/245767
       ResourceProvider::ResourceId resource_id_;
       scoped_ptr<ResourcePool::Resource> resource_;
       GLenum resource_format_;
       bool forced_upload_;
+      TileRasterMode raster_mode_;
+      RasterWorkerPool::RasterTask raster_task_;
   };
 
 
   ManagedTileState();
   ~ManagedTileState();
 
   scoped_ptr<base::Value> AsValue() const;
 
   // Persisted state: valid all the time.
   TileVersion tile_version;

[reveman, 2013/06/05 14:25:13]

Why not just replace |tile_version| with:
typedef std::map<TileRasterMode, TileVersion> TileVersionMap;
TileVersionMap tile_versions;
or maybe:
TileVersion tile_versions[NUM_RASTER_MODES];

The tile manager code would essentially be the same as before expect anywhere
you access |tile_version| you would do tile_versions[raster_mode] instead.

"TileVersion tile_versions[NUM_RASTER_MODES]" is probably much better than using
std::map. The advantage of the map would be that you could save some memory when
we have a lot of different tile versions but that's not the case right now and
the simple array is likely much more efficient.

+
+  typedef std::map<TileRasterMode, TileVersion*> TileVersionMap;
+  TileVersionMap pending_tile_versions;
+
   bool picture_pile_analyzed;
   PicturePileImpl::Analysis picture_pile_analysis;
-  RasterWorkerPool::RasterTask raster_task;
 
   // Ephemeral state, valid only during TileManager::ManageTiles.
   bool is_in_never_bin_on_both_trees() const {
     return bin[HIGH_PRIORITY_BIN] == NEVER_BIN &&
            bin[LOW_PRIORITY_BIN] == NEVER_BIN;
   }
   bool is_in_now_bin_on_either_tree() const {
     return bin[HIGH_PRIORITY_BIN] == NOW_BIN ||
            bin[LOW_PRIORITY_BIN] == NOW_BIN;
   }
 
   TileManagerBin bin[NUM_BIN_PRIORITIES];
   TileManagerBin tree_bin[NUM_TREES];
 
   // The bin that the tile would have if the GPU memory manager had
   // a maximally permissive policy, send to the GPU memory manager
   // to determine policy.
   TileManagerBin gpu_memmgr_stats_bin;
   TileResolution resolution;
   bool required_for_activation;
   float time_to_needed_in_seconds;
   float distance_to_visible_in_pixels;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_MANAGED_TILE_STATE_H_