cc: Use a ListContainer for DisplayItemList to reduce allocations.

ui/compositor/clip_transform_recorder.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 UI_COMPOSITOR_CLIP_TRANSFORM_RECORDER_H_
 #define UI_COMPOSITOR_CLIP_TRANSFORM_RECORDER_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 22 matching lines @@
  public:
   explicit ClipTransformRecorder(const PaintContext& context);
   ~ClipTransformRecorder();
 
   void ClipRect(const gfx::Rect& clip_rect);
   void ClipPath(const gfx::Path& clip_path);
   void ClipPathWithAntiAliasing(const gfx::Path& clip_path);
   void Transform(const gfx::Transform& transform);
 
  private:
+  enum Closer {
+    CLIP_RECT,
+    CLIP_PATH,
+    TRANSFORM,
+  };
   const PaintContext& context_;
-  std::vector<cc::DisplayItem*> closers_;
+  std::vector<Closer> closers_;
 
   DISALLOW_COPY_AND_ASSIGN(ClipTransformRecorder);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_CLIP_TRANSFORM_RECORDER_H_