cc: Devirtualize DisplayItem::ExternalMemoryUsage().

cc/playback/filter_display_item.cc

Index: cc/playback/filter_display_item.cc
diff --git a/cc/playback/filter_display_item.cc b/cc/playback/filter_display_item.cc
index 212d6e43570795910409185a73aed2b2c688e4ad..41d87840fbbeb8a886f5ff75e431d3718e29ef23 100644
--- a/cc/playback/filter_display_item.cc
+++ b/cc/playback/filter_display_item.cc
@@ -21,11 +21,13 @@ namespace cc {
 
 FilterDisplayItem::FilterDisplayItem(const FilterOperations& filters,
                                      const gfx::RectF& bounds,
-                                     const gfx::PointF& origin) {
+                                     const gfx::PointF& origin)
+    : DisplayItem(FILTER) {
   SetNew(filters, bounds, origin);
 }
 
-FilterDisplayItem::FilterDisplayItem(const proto::DisplayItem& proto) {
+FilterDisplayItem::FilterDisplayItem(const proto::DisplayItem& proto)
+    : DisplayItem(FILTER) {
   DCHECK_EQ(proto::DisplayItem::Type_Filter, proto.type());
 
   const proto::FilterDisplayItem& details = proto.filter_item();
@@ -82,15 +84,10 @@ void FilterDisplayItem::AsValueInto(
       bounds_.ToString().c_str(), visual_rect.ToString().c_str()));
 }
 
-size_t FilterDisplayItem::ExternalMemoryUsage() const {
-  // FilterOperations doesn't expose its capacity, but size is probably good
-  // enough.
-  return filters_.size() * sizeof(filters_.at(0));
-}
-
-EndFilterDisplayItem::EndFilterDisplayItem() {}
+EndFilterDisplayItem::EndFilterDisplayItem() : DisplayItem(END_FILTER) {}
 
-EndFilterDisplayItem::EndFilterDisplayItem(const proto::DisplayItem& proto) {
+EndFilterDisplayItem::EndFilterDisplayItem(const proto::DisplayItem& proto)
+    : DisplayItem(END_FILTER) {
   DCHECK_EQ(proto::DisplayItem::Type_EndFilter, proto.type());
 }
 
@@ -114,8 +111,4 @@ void EndFilterDisplayItem::AsValueInto(
                          visual_rect.ToString().c_str()));
 }
 
-size_t EndFilterDisplayItem::ExternalMemoryUsage() const {
-  return 0;
-}
-
 }  // namespace cc