Explicitly detach remote window from its frame.

third_party/WebKit/Source/core/frame/RemoteFrame.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/frame/RemoteFrame.h"
 
 #include "bindings/core/v8/WindowProxy.h"
 #include "bindings/core/v8/WindowProxyManager.h"
 #include "core/dom/RemoteSecurityContext.h"
@@ skipping 127 matching lines @@
 void RemoteFrame::frameRectsChanged(const IntRect& frameRect)
 {
     remoteFrameClient()->frameRectsChanged(frameRect);
 }
 
 void RemoteFrame::setView(PassRefPtrWillBeRawPtr<RemoteFrameView> view)
 {
     // Oilpan: as RemoteFrameView performs no finalization actions,
     // no explicit dispose() of it needed here. (cf. FrameView::dispose().)
     m_view = view;
+
+    // ... the RemoteDOMWindow will need to be informed of detachment,
+    // as otherwise it will keep a strong reference back to this RemoteFrame.
+    // That combined with wrappers (owned and kept alive by RemoteFrame) keeping
+    // persistent strong references to RemoteDOMWindow will prevent the GCing
+    // of all these objects. Break the cycle by notifying of detachment.
+    if (!m_view)
+        m_domWindow->frameDetached();
 }
 
 void RemoteFrame::createView()
 {
     // If the RemoteFrame does not have a LocalFrame parent, there's no need to
     // create a widget for it.
     if (!deprecatedLocalOwner())
         return;
 
     ASSERT(!deprecatedLocalOwner()->ownedWidget());
@@ skipping 15 matching lines @@
         GraphicsLayer::unregisterContentsLayer(m_remotePlatformLayer);
     m_remotePlatformLayer = layer;
     if (m_remotePlatformLayer)
         GraphicsLayer::registerContentsLayer(layer);
 
     ASSERT(owner());
     toHTMLFrameOwnerElement(owner())->setNeedsCompositingUpdate();
 }
 
 } // namespace blink