cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/resources/float_clip_display_item.h

Index: cc/resources/float_clip_display_item.h
diff --git a/cc/resources/float_clip_display_item.h b/cc/resources/float_clip_display_item.h
index af88c50a20ace409d886bbea5db7a8cea9e3b3dc..72857fc7d7cd9cdfa35cb7bcf16f0f9a18258ec0 100644
--- a/cc/resources/float_clip_display_item.h
+++ b/cc/resources/float_clip_display_item.h
@@ -19,11 +19,10 @@ namespace cc {
 
 class CC_EXPORT FloatClipDisplayItem : public DisplayItem {
  public:
+  FloatClipDisplayItem();
   ~FloatClipDisplayItem() override;
 
-  static scoped_ptr<FloatClipDisplayItem> Create(gfx::RectF clip_rect) {
-    return make_scoped_ptr(new FloatClipDisplayItem(clip_rect));
-  }
+  void SetNew(const gfx::RectF& clip_rect);
 
   void Raster(SkCanvas* canvas, SkDrawPictureCallback* callback) const override;
 
@@ -41,6 +40,7 @@ class CC_EXPORT FloatClipDisplayItem : public DisplayItem {
 
 class CC_EXPORT EndFloatClipDisplayItem : public DisplayItem {
  public:
+  EndFloatClipDisplayItem();
   ~EndFloatClipDisplayItem() override;
 
   static scoped_ptr<EndFloatClipDisplayItem> Create() {
@@ -53,9 +53,6 @@ class CC_EXPORT EndFloatClipDisplayItem : public DisplayItem {
   int ApproximateOpCount() const override;
   size_t PictureMemoryUsage() const override;
   void AsValueInto(base::trace_event::TracedValue* array) const override;
-
- protected:
-  EndFloatClipDisplayItem();
 };
 
 }  // namespace cc