cc: Low quality support for low res tiles

cc/resources/tile.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_TILE_H_
 #define CC_RESOURCES_TILE_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "cc/resources/managed_tile_state.h"
 #include "cc/resources/picture_pile_impl.h"
+#include "cc/resources/tile_manager.h"
 #include "cc/resources/tile_priority.h"
 #include "cc/trees/layer_tree_host_impl.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 namespace cc {
 
 class Tile;
-class TileManager;
 
 class CC_EXPORT Tile : public base::RefCounted<Tile> {
  public:
   Tile(TileManager* tile_manager,
        PicturePileImpl* picture_pile,
        gfx::Size tile_size,
        gfx::Rect content_rect,
        gfx::Rect opaque_rect,
        float contents_scale,
        int layer_id,
        int source_frame_number);
 
   PicturePileImpl* picture_pile() {
     return picture_pile_.get();
   }
 
+  const PicturePileImpl* picture_pile() const {
+    return picture_pile_.get();
+  }
+
   const TilePriority& priority(WhichTree tree) const {
     return priority_[tree];
   }
 
   TilePriority combined_priority() const {
     return TilePriority(priority_[ACTIVE_TREE],
                         priority_[PENDING_TREE]);
   }
 
   void SetPriority(WhichTree tree, const TilePriority& priority) {
     priority_[tree] = priority;
   }
 
   void mark_required_for_activation() {
     priority_[PENDING_TREE].required_for_activation = true;
   }
 
   bool required_for_activation() const {
     return priority_[PENDING_TREE].required_for_activation;
   }
 
   scoped_ptr<base::Value> AsValue() const;
 
   const ManagedTileState::TileVersion& tile_version() const {

[reveman, 2013/06/05 18:01:32]

tile_version() magically returning the tile version that is preferred for
drawing is a bit weird.

How about we add:
bool Tile::IsReadyToDraw() and
TileRasterMode Tile::GetRasterModeThatIsReadyToDraw();
or just:
bool Tile::IsReadyToDraw(TileRasterMode* ready_to_draw_mode);

and make these tile_version() functions take a TileRasterMode as parameter and
just return tile_versions[mode]?

this way you also make sure there's no old tile_version() call sites you forgot
that need to be adjusted.

[vmpstr, 2013/06/06 01:54:20]

Done.

-    return managed_state_.tile_version;
+    for (int mode = NUM_RASTER_MODES - 1; mode >= 0; --mode) {
+      if (managed_state_.tile_versions[mode].IsReadyToDraw())
+        return managed_state_.tile_versions[mode];
+    }
+    return managed_state_.tile_versions[managed_state_.raster_mode];
   }
   ManagedTileState::TileVersion& tile_version() {
-    return managed_state_.tile_version;
+    for (int mode = NUM_RASTER_MODES - 1; mode >= 0; --mode) {
+      if (managed_state_.tile_versions[mode].IsReadyToDraw())
+        return managed_state_.tile_versions[mode];
+    }
+    return managed_state_.tile_versions[managed_state_.raster_mode];
   }
 
   gfx::Rect opaque_rect() const { return opaque_rect_; }
   bool has_text() const {
     return managed_state_.picture_pile_analysis.has_text;
   }
 
   float contents_scale() const { return contents_scale_; }
   gfx::Rect content_rect() const { return content_rect_; }
 
   int layer_id() const { return layer_id_; }
 
   int source_frame_number() const { return source_frame_number_; }
 
   void set_picture_pile(scoped_refptr<PicturePileImpl> pile) {
     DCHECK(pile->CanRaster(contents_scale_, content_rect_));
     picture_pile_ = pile;
   }
 
   // For test only methods.
   bool HasRasterTaskForTesting() const {
-    return !managed_state().raster_task.is_null();
+    for (int mode = 0; mode < NUM_RASTER_MODES; ++mode) {
+      if (!managed_state().tile_versions[mode].raster_task_.is_null())
+        return true;
+    }
+    return false;
   }
   void ResetRasterTaskForTesting() {
-    managed_state().raster_task.Reset();
+    for (int mode = 0; mode < NUM_RASTER_MODES; ++mode) {
+      if (!managed_state().tile_versions[mode].raster_task_.is_null())

[reveman, 2013/06/05 18:01:32]

can you remove this and always call Reset instead?

[vmpstr, 2013/06/06 01:54:20]

Done.

+        managed_state().tile_versions[mode].raster_task_.Reset();
+    }
   }
 
  private:
   // Methods called by by tile manager.
   friend class TileManager;
   friend class BinComparator;
   ManagedTileState& managed_state() { return managed_state_; }
   const ManagedTileState& managed_state() const { return managed_state_; }
 
   inline size_t bytes_consumed_if_allocated() const {
@@ skipping 16 matching lines @@
   ManagedTileState managed_state_;
   int layer_id_;
   int source_frame_number_;
 
   DISALLOW_COPY_AND_ASSIGN(Tile);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILE_H_