Move Frame to the Oilpan heap.

Source/core/frame/FrameView.h

Index: Source/core/frame/FrameView.h
diff --git a/Source/core/frame/FrameView.h b/Source/core/frame/FrameView.h
index dffc6f79fa8f9ec0e1199240eb2218c26f5f2bbd..9db32f432b53ac9eb7053272ae50b25e05dd5082 100644
--- a/Source/core/frame/FrameView.h
+++ b/Source/core/frame/FrameView.h
@@ -57,6 +57,7 @@ class RenderWidget;
 
 typedef unsigned long long DOMTimeStamp;
 
+// FIXME: Oilpan: move FrameView (or ScrollView) to the heap.
 class FrameView FINAL : public ScrollView {
 public:
     friend class RenderView;
@@ -414,7 +415,9 @@ private:
     // FIXME: These are just "children" of the FrameView and should be RefPtr<Widget> instead.
     WillBePersistentHeapHashSet<RefPtrWillBeMember<RenderWidget> > m_widgets;
 
-    RefPtr<LocalFrame> m_frame;
+    // FIXME: Oilpan: the persistent back reference looks too strong, but it
+    // 'emulates' the RefPtr-cycle that is kept between the two objects non-Oilpan.

[haraken, 2014/09/08 07:25:58]

Help me understand: What's a lifetime relationship between LocalFrame and
FrameView in non-oilpan? I want to understand why the reference cycle between
LocalFrame and FrameView is not a problem.

[dcheng, 2014/09/08 08:34:17]

LocalFrame and FrameView ref each other, but when a LocalFrame is detached by
FrameLoader::detachFromParent(), FrameLoader clears LocalFrame's ref to
FrameView which should break the cycle.

+    RefPtrWillBePersistent<LocalFrame> m_frame;
 
     bool m_doFullPaintInvalidation;