cc: Use a ListContainer for DisplayItemList to reduce allocations.

cc/resources/float_clip_display_item.cc

Index: cc/resources/float_clip_display_item.cc
diff --git a/cc/resources/float_clip_display_item.cc b/cc/resources/float_clip_display_item.cc
index ba98fe5bdc0a44b09bf6d798a9cf8555976b9b25..47653a6eab36e96f947e7201149b8cace4b5aa41 100644
--- a/cc/resources/float_clip_display_item.cc
+++ b/cc/resources/float_clip_display_item.cc
@@ -11,13 +11,16 @@
 
 namespace cc {
 
-FloatClipDisplayItem::FloatClipDisplayItem(gfx::RectF clip_rect)
-    : clip_rect_(clip_rect) {
+FloatClipDisplayItem::FloatClipDisplayItem() {
 }
 
 FloatClipDisplayItem::~FloatClipDisplayItem() {
 }
 
+void FloatClipDisplayItem::SetNew(const gfx::RectF& clip_rect) {
+  clip_rect_ = clip_rect;
+}
+
 void FloatClipDisplayItem::Raster(SkCanvas* canvas,
                                   SkDrawPictureCallback* callback) const {
   canvas->save();