cc: Use reverse spiral iterator in tiling eviction.

cc/resources/picture_layer_tiling_perftest.cc

 // 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.
 
 #include "cc/debug/lap_timer.h"
 #include "cc/resources/picture_layer_tiling.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/scoped_resource.h"
 #include "cc/test/fake_output_surface.h"
 #include "cc/test/fake_output_surface_client.h"
@@ skipping 171 matching lines @@
   void RunEvictionIteratorConstructTest(const std::string& test_name,
                                         const gfx::Rect& viewport) {
     gfx::Size bounds(viewport.size());
     picture_layer_tiling_ =
         PictureLayerTiling::Create(1, bounds, &picture_layer_tiling_client_);
     picture_layer_tiling_client_.set_tree(ACTIVE_TREE);
     picture_layer_tiling_->ComputeTilePriorityRects(
         ACTIVE_TREE, viewport, 1.0f, 1.0, Occlusion());
 
     timer_.Reset();
-    TreePriority priorities[] = {SAME_PRIORITY_FOR_BOTH_TREES,
-                                 SMOOTHNESS_TAKES_PRIORITY,
-                                 NEW_CONTENT_TAKES_PRIORITY};
-    int priority_count = 0;
     do {
       PictureLayerTiling::TilingEvictionTileIterator it(
           picture_layer_tiling_.get(),
-          priorities[priority_count],
           PictureLayerTiling::NOW);
-      priority_count = (priority_count + 1) % arraysize(priorities);
       timer_.NextLap();
     } while (!timer_.HasTimeLimitExpired());
 
     perf_test::PrintResult("tiling_eviction_tile_iterator_construct",
                            "",
                            test_name,
                            timer_.LapsPerSecond(),
                            "runs/s",
                            true);
   }
 
   void RunEvictionIteratorConstructAndIterateTest(const std::string& test_name,
                                                   int num_tiles,
                                                   const gfx::Rect& viewport) {
     gfx::Size bounds(10000, 10000);
     picture_layer_tiling_ =
         PictureLayerTiling::Create(1, bounds, &picture_layer_tiling_client_);
     picture_layer_tiling_client_.set_tree(ACTIVE_TREE);
     picture_layer_tiling_->ComputeTilePriorityRects(
         ACTIVE_TREE, viewport, 1.0f, 1.0, Occlusion());
 
-    TreePriority priorities[] = {SAME_PRIORITY_FOR_BOTH_TREES,
-                                 SMOOTHNESS_TAKES_PRIORITY,
-                                 NEW_CONTENT_TAKES_PRIORITY};
-
     // Ensure all tiles have resources.
     std::vector<Tile*> all_tiles = picture_layer_tiling_->AllTilesForTesting();
     for (std::vector<Tile*>::iterator tile_it = all_tiles.begin();
          tile_it != all_tiles.end();
          ++tile_it) {
       Tile* tile = *tile_it;
       ManagedTileState::DrawInfo& draw_info = tile->draw_info();
       draw_info.SetResourceForTesting(
           ScopedResource::Create(resource_provider_.get()).Pass());
     }
 
-    int priority_count = 0;
     timer_.Reset();
     do {
       int count = num_tiles;
       PictureLayerTiling::TilingEvictionTileIterator it(
           picture_layer_tiling_.get(),
-          priorities[priority_count],
           PictureLayerTiling::EVENTUALLY);
       while (count--) {
         ASSERT_TRUE(it) << "count: " << count;
         ASSERT_TRUE(*it != NULL) << "count: " << count;
         ++it;
       }
-      priority_count = (priority_count + 1) % arraysize(priorities);
       timer_.NextLap();
     } while (!timer_.HasTimeLimitExpired());
 
     // Remove all resources from tiles to make sure the tile version destructor
     // doesn't complain.
     for (std::vector<Tile*>::iterator tile_it = all_tiles.begin();
          tile_it != all_tiles.end();
          ++tile_it) {
       Tile* tile = *tile_it;
       ManagedTileState::DrawInfo& draw_info = tile->draw_info();
@@ skipping 89 matching lines @@
       "32_500x500", 32, gfx::Rect(0, 0, 500, 500));
   RunEvictionIteratorConstructAndIterateTest(
       "64_100x100", 64, gfx::Rect(0, 0, 100, 100));
   RunEvictionIteratorConstructAndIterateTest(
       "64_500x500", 64, gfx::Rect(0, 0, 500, 500));
 }
 
 }  // namespace
 
 }  // namespace cc