cc: Optimize decode scheduling for checker-images.

cc/tiles/tiling_set_raster_queue_all.cc

 // Copyright 2014 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.
 
 #include "cc/tiles/tiling_set_raster_queue_all.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 182 matching lines @@
   if (!IsTileValid(tile)) {
     current_tile_ = PrioritizedTile();
     return false;
   }
   current_tile_ = tiling_->MakePrioritizedTile(tile, priority_rect_type_);
   return true;
 }
 
 bool TilingSetRasterQueueAll::OnePriorityRectIterator::IsTileValid(
     const Tile* tile) const {
-  if (!tile || !TileNeedsRaster(tile))
+  if (!tile)
     return false;
+
+  // A tile is valid for raster if it needs raster and is unoccluded.
+  bool tile_is_valid_for_raster =
+      tile->draw_info().NeedsRaster() && !tiling_->IsTileOccluded(tile);
+
+  // A tile is not valid for the raster queue if it is not valid for raster or
+  // processing for checker-images.
+  if (!tile_is_valid_for_raster) {
+    bool tile_is_valid_for_checker_images =
+        tile->draw_info().is_checker_imaged() &&
+        tiling_->ShouldDecodeCheckeredImagesForTile(tile);
+    if (!tile_is_valid_for_checker_images)
+      return false;
+  }
+
   // After the pending visible rect has been processed, we must return false
   // for pending visible rect tiles as tiling iterators do not ignore those
   // tiles.
   if (priority_rect_type_ > PictureLayerTiling::PENDING_VISIBLE_RECT) {
     gfx::Rect tile_bounds = tiling_data_->TileBounds(tile->tiling_i_index(),
                                                      tile->tiling_j_index());
     if (pending_visible_rect_.Intersects(tile_bounds))
       return false;
   }
   return true;
@@ skipping 223 matching lines @@
         current_tile_ = PrioritizedTile();
         return *this;
       }
       current_tile_ = *eventually_iterator_;
       break;
   }
   return *this;
 }
 
 }  // namespace cc