Move Frame to the Oilpan heap.

Source/web/WebViewImpl.h

Index: Source/web/WebViewImpl.h
diff --git a/Source/web/WebViewImpl.h b/Source/web/WebViewImpl.h
index 544e21fffe25f1ca93b0c4b8ba684f79e951a748..11d3a996ef95efd8ba7f79163b3a4c633ede4faf 100644
--- a/Source/web/WebViewImpl.h
+++ b/Source/web/WebViewImpl.h
@@ -35,6 +35,7 @@
 #include "platform/geometry/IntPoint.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/GraphicsLayer.h"
+#include "platform/heap/Handle.h"
 #include "public/platform/WebGestureCurveTarget.h"
 #include "public/platform/WebLayer.h"
 #include "public/platform/WebPoint.h"
@@ -72,6 +73,7 @@ class UserGestureToken;
 class WebActiveGestureAnimation;
 class WebDevToolsAgentPrivate;
 class WebLocalFrameImpl;
+class WebRemoteFrameImpl;
 class WebImage;
 class WebPagePopupImpl;
 class WebPlugin;
@@ -601,6 +603,18 @@ private:
 
     OwnPtrWillBePersistent<Page> m_page;
 
+#if ENABLE(OILPAN)
+    // With Oilpan, the WebViewImpl object keeps a strong reference to one kind of main
+    // frame, so as to keep it alive until the view lets it go.
+    //
+    // In the non-Oilpan case, the ref-counted frame is instead created and returned with
+    // a ref count that must be balanced by eventually calling close() on the
+    // Web*FrameImpl object. That close() call is also assumed for Oilpan, but we need
+    // to keep the object alive until that time. Hence these mutually-exclusive Persistent<>s.
+    Persistent<WebLocalFrameImpl> m_localMainFrame;
+    Persistent<WebRemoteFrameImpl> m_remoteMainFrame;

[dcheng, 2014/09/11 17:03:10]

Page also has a main frame field. It feels redundant to maintain two of them.
Why can't we just make Page's m_mainFrame Persistent?

[sof, 2014/09/12 10:06:21]

This is about retaining the Web{Local,Remote}FrameImpl GCed objects, Page keeps
a Frame. Something close to the web view will have to keep those alive, I think.

But how to represent Page::m_mainFrame in Oilpan is something that needs to be
tidied up.

+#endif
+
     // An object that can be used to manipulate m_page->settings() without linking
     // against WebCore. This is lazily allocated the first time GetWebSettings()
     // is called.
@@ -708,7 +722,7 @@ private:
     int m_flingModifier;
     bool m_flingSourceDevice;
     Vector<OwnPtr<LinkHighlight> > m_linkHighlights;
-    OwnPtr<FullscreenController> m_fullscreenController;
+    OwnPtrWillBePersistent<FullscreenController> m_fullscreenController;
 
     bool m_showFPSCounter;
     bool m_showPaintRects;