Make classes and structures in core/frame fast-allocated.

Source/core/frame/RootFrameViewport.h

Index: Source/core/frame/RootFrameViewport.h
diff --git a/Source/core/frame/RootFrameViewport.h b/Source/core/frame/RootFrameViewport.h
index 20b7ce02a7681a927aa1d5b950213d0397ee9dd0..14bf32bbd7904682eda8e16df0c100a3137af06d 100644
--- a/Source/core/frame/RootFrameViewport.h
+++ b/Source/core/frame/RootFrameViewport.h
@@ -22,6 +22,7 @@ class LayoutRect;
 // the layout viewport. Thus, we could say this class is a decorator on the
 // FrameView scrollable area that adds pinch-zoom semantics to scrolling.
 class CORE_EXPORT RootFrameViewport final : public NoBaseWillBeGarbageCollectedFinalized<RootFrameViewport>, public ScrollableArea {
+    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(RootFrameViewport);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RootFrameViewport);
 public:
     static PassOwnPtrWillBeRawPtr<RootFrameViewport> create(ScrollableArea& visualViewport, ScrollableArea& layoutViewport, bool invertScrollOrder = false)