cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/resources/clip_path_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_CLIP_PATH_DISPLAY_ITEM_H_
 #define CC_RESOURCES_CLIP_PATH_DISPLAY_ITEM_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/resources/display_item.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkRegion.h"
 
 class SkCanvas;
 class SkDrawPictureCallback;
 
 namespace cc {
 
 class CC_EXPORT ClipPathDisplayItem : public DisplayItem {
  public:
+  ClipPathDisplayItem();
   ~ClipPathDisplayItem() override;
 
-  static scoped_ptr<ClipPathDisplayItem> Create(const SkPath& path,
-                                                SkRegion::Op clip_op,
-                                                bool antialias) {
-    return make_scoped_ptr(new ClipPathDisplayItem(path, clip_op, antialias));
-  }
+  void SetNew(const SkPath& path, SkRegion::Op clip_op, bool antialias);
 
   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:
   ClipPathDisplayItem(const SkPath& path, SkRegion::Op clip_op, bool antialias);
 
  private:
   SkPath clip_path_;
   SkRegion::Op clip_op_;
   bool antialias_;
 };
 
 class CC_EXPORT EndClipPathDisplayItem : public DisplayItem {
  public:
+  EndClipPathDisplayItem();
   ~EndClipPathDisplayItem() override;
 
   static scoped_ptr<EndClipPathDisplayItem> Create() {
     return make_scoped_ptr(new EndClipPathDisplayItem());
   }
 
   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:
-  EndClipPathDisplayItem();
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_CLIP_PATH_DISPLAY_ITEM_H_