cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/resources/compositing_display_item.h

 // 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.
 
 #ifndef CC_RESOURCES_COMPOSITING_DISPLAY_ITEM_H_
 #define CC_RESOURCES_COMPOSITING_DISPLAY_ITEM_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/resources/display_item.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/geometry/rect_f.h"
 
 class SkCanvas;
 class SkDrawPictureCallback;
 
 namespace cc {
 
 class CC_EXPORT CompositingDisplayItem : public DisplayItem {
  public:
+  CompositingDisplayItem();
   ~CompositingDisplayItem() override;
 
-  static scoped_ptr<CompositingDisplayItem> Create(
-      uint8_t alpha,
-      SkXfermode::Mode xfermode,
-      SkRect* bounds,
-      skia::RefPtr<SkColorFilter> color_filter) {
-    return make_scoped_ptr(
-        new CompositingDisplayItem(alpha, xfermode, bounds, color_filter));
-  }
+  void SetNew(uint8_t alpha,
+              SkXfermode::Mode xfermode,
+              SkRect* bounds,
+              skia::RefPtr<SkColorFilter> color_filter);
 
   void Raster(SkCanvas* canvas, SkDrawPictureCallback* callback) const override;
 
   bool IsSuitableForGpuRasterization() const override;
   int ApproximateOpCount() const override;
   size_t PictureMemoryUsage() const override;
   void AsValueInto(base::trace_event::TracedValue* array) const override;
 
  protected:
   CompositingDisplayItem(uint8_t alpha,
                          SkXfermode::Mode,
                          SkRect* bounds,
                          skia::RefPtr<SkColorFilter>);
 
  private:
   uint8_t alpha_;
   SkXfermode::Mode xfermode_;
   bool has_bounds_;
   SkRect bounds_;
   skia::RefPtr<SkColorFilter> color_filter_;
 };
 
 class CC_EXPORT EndCompositingDisplayItem : public DisplayItem {
  public:
+  EndCompositingDisplayItem();
   ~EndCompositingDisplayItem() override;
 
   static scoped_ptr<EndCompositingDisplayItem> Create() {
     return make_scoped_ptr(new EndCompositingDisplayItem());
   }
 
   void Raster(SkCanvas* canvas, SkDrawPictureCallback* callback) const override;
 
   bool IsSuitableForGpuRasterization() const override;
   int ApproximateOpCount() const override;
   size_t PictureMemoryUsage() const override;
   void AsValueInto(base::trace_event::TracedValue* array) const override;
-
- protected:
-  EndCompositingDisplayItem();
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_COMPOSITING_DISPLAY_ITEM_H_