cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/layers/picture_image_layer_unittest.cc

 // Copyright 2015 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/layers/picture_image_layer.h"
 
 #include "cc/resources/display_item.h"
 #include "cc/test/skia_common.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ skipping 21 matching lines @@
 
   layer->SetBitmap(image_bitmap);
   layer->SetBounds(gfx::Size(layer_rect.width(), layer_rect.height()));
 
   bool use_cached_picture = false;
   scoped_refptr<DisplayItemList> display_list =
       DisplayItemList::Create(layer_rect, use_cached_picture);
   layer->PaintContentsToDisplayList(
       display_list.get(), layer_rect,
       ContentLayerClient::PAINTING_BEHAVIOR_NORMAL);
+  display_list->ProcessAppendedItems();
   unsigned char actual_pixels[4 * 200 * 200] = {0};
   DrawDisplayList(actual_pixels, layer_rect, display_list);
 
   EXPECT_EQ(0, memcmp(actual_pixels, image_pixels, 4 * 200 * 200));
 }
 
 TEST(PictureImageLayerTest, PaintContentsToCachedDisplayList) {
   scoped_refptr<PictureImageLayer> layer = PictureImageLayer::Create();
   gfx::Rect layer_rect(200, 200);
 
@@ skipping 11 matching lines @@
 
   layer->SetBitmap(image_bitmap);
   layer->SetBounds(gfx::Size(layer_rect.width(), layer_rect.height()));
 
   bool use_cached_picture = true;
   scoped_refptr<DisplayItemList> display_list =
       DisplayItemList::Create(layer_rect, use_cached_picture);
   layer->PaintContentsToDisplayList(
       display_list.get(), layer_rect,
       ContentLayerClient::PAINTING_BEHAVIOR_NORMAL);
+  display_list->ProcessAppendedItems();
   display_list->CreateAndCacheSkPicture();
   unsigned char actual_pixels[4 * 200 * 200] = {0};
   DrawDisplayList(actual_pixels, layer_rect, display_list);
 
   EXPECT_EQ(0, memcmp(actual_pixels, image_pixels, 4 * 200 * 200));
 }
 
 }  // namespace
 }  // namespace cc