cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/resources/clip_display_item.cc

Index: cc/resources/clip_display_item.cc
diff --git a/cc/resources/clip_display_item.cc b/cc/resources/clip_display_item.cc
index b124ba1a1a77c08fd6d3a01175dd601b31dfdea6..c5c43620dde1237219473d2b9a072b0fe3db00ff 100644
--- a/cc/resources/clip_display_item.cc
+++ b/cc/resources/clip_display_item.cc
@@ -13,14 +13,18 @@
 
 namespace cc {
 
-ClipDisplayItem::ClipDisplayItem(gfx::Rect clip_rect,
-                                 const std::vector<SkRRect>& rounded_clip_rects)
-    : clip_rect_(clip_rect), rounded_clip_rects_(rounded_clip_rects) {
+ClipDisplayItem::ClipDisplayItem() {
 }
 
 ClipDisplayItem::~ClipDisplayItem() {
 }
 
+void ClipDisplayItem::SetNew(gfx::Rect clip_rect,
+                             const std::vector<SkRRect>& rounded_clip_rects) {
+  clip_rect_ = clip_rect;
+  rounded_clip_rects_ = rounded_clip_rects;
+}
+
 void ClipDisplayItem::Raster(SkCanvas* canvas,
                              SkDrawPictureCallback* callback) const {
   canvas->save();