cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/resources/drawing_display_item.cc

Index: cc/resources/drawing_display_item.cc
diff --git a/cc/resources/drawing_display_item.cc b/cc/resources/drawing_display_item.cc
index 333d29862274b5023f019e8c103394eb3d80fa0f..97864b3228ee5695b5aacc1f140a34657bb713f9 100644
--- a/cc/resources/drawing_display_item.cc
+++ b/cc/resources/drawing_display_item.cc
@@ -17,13 +17,16 @@
 
 namespace cc {
 
-DrawingDisplayItem::DrawingDisplayItem(skia::RefPtr<SkPicture> picture)
-    : picture_(picture) {
+DrawingDisplayItem::DrawingDisplayItem() {
 }
 
 DrawingDisplayItem::~DrawingDisplayItem() {
 }
 
+void DrawingDisplayItem::SetNew(skia::RefPtr<SkPicture> picture) {
+  picture_ = picture.Pass();
+}
+
 void DrawingDisplayItem::Raster(SkCanvas* canvas,
                                 SkDrawPictureCallback* callback) const {
   // SkPicture always does a wrapping save/restore on the canvas, so it is not
@@ -62,8 +65,8 @@ void DrawingDisplayItem::AsValueInto(
   array->EndDictionary();
 }
 
-scoped_ptr<DrawingDisplayItem> DrawingDisplayItem::Clone() {
-  return Create(picture_);
+void DrawingDisplayItem::CloneTo(DrawingDisplayItem* item) const {
+  item->SetNew(picture_);
 }
 
 }  // namespace cc