Refresh Frame(Loader) detach() related comments.

Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
@@ skipping 706 matching lines @@
 
     LayoutSize m_size;
 
     typedef HashSet<RefPtr<LayoutEmbeddedObject>> EmbeddedObjectSet;
     EmbeddedObjectSet m_partUpdateSet;
 
     // FIXME: These are just "children" of the FrameView and should be RefPtrWillBeMember<Widget> instead.
     HashSet<RefPtr<LayoutPart>> m_parts;
 
     // The RefPtr cycle between LocalFrame and FrameView is broken
-    // when a LocalFrame is detached by FrameLoader::detachFromParent().
+    // when a LocalFrame is detached (LocalFrame::detach()).

[dcheng, 2015/07/13 17:27:51]

Personally, I think 'by' is a bit clearer since it avoids the double parens. But
I don't really care.

     // It clears the LocalFrame's m_view reference via setView(nullptr).
     //
     // For Oilpan, Member reference cycles pose no problem, but
-    // LocalFrame's FrameView is also cleared by setView(). This additionally
-    // triggers FrameView::dispose(), which performs the operations
-    // that cannot be delayed until finalization time.
+    // LocalFrame's FrameView is also cleared by setView() to keep
+    // the observable lifespan of LocalFrame::view() identical.
     RefPtrWillBeMember<LocalFrame> m_frame;
 
     WebDisplayMode m_displayMode;
 
     bool m_doFullPaintInvalidation;
 
     bool m_canHaveScrollbars;
     unsigned m_slowRepaintObjectCount;
 
     bool m_hasPendingLayout;
@@ skipping 121 matching lines @@
     static const unsigned visualPixelThreshold = 32 * 32;
     if (m_visuallyNonEmptyPixelCount > visualPixelThreshold)
         setIsVisuallyNonEmpty();
 }
 
 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView());
 
 } // namespace blink
 
 #endif // FrameView_h