Clear opener when frame is detached.

third_party/WebKit/Source/web/WebFrame.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 "public/web/WebFrame.h"
 
 #include "bindings/core/v8/WindowProxyManager.h"
 #include "core/HTMLNames.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
@@ skipping 273 matching lines @@
       m_nextSibling(0),
       m_firstChild(0),
       m_lastChild(0),
       m_opener(0),
       m_openedFrameTracker(new OpenedFrameTracker) {}
 
 WebFrame::~WebFrame() {
   m_openedFrameTracker.reset(0);
 }
 
-ALWAYS_INLINE bool WebFrame::isFrameAlive(const WebFrame* frame) {
-  if (!frame)
-    return true;
-
-  if (frame->isWebLocalFrame())
-    return ThreadHeap::isHeapObjectAlive(toWebLocalFrameImpl(frame));
-
-  return ThreadHeap::isHeapObjectAlive(toWebRemoteFrameImpl(frame));
-}
-
 void WebFrame::traceFrame(Visitor* visitor, WebFrame* frame) {
   if (!frame)
     return;
 
   if (frame->isWebLocalFrame())
     visitor->trace(toWebLocalFrameImpl(frame));
   else
     visitor->trace(toWebRemoteFrameImpl(frame));
 }
 
 void WebFrame::traceFrames(Visitor* visitor, WebFrame* frame) {
   DCHECK(frame);
   traceFrame(visitor, frame->m_parent);
   for (WebFrame* child = frame->firstChild(); child;
        child = child->nextSibling())
     traceFrame(visitor, child);
-  // m_opener is a weak reference.
-  frame->m_openedFrameTracker->traceFrames(visitor);
 }
 
-void WebFrame::clearWeakFrames(Visitor* visitor) {
-  if (!isFrameAlive(m_opener))
-    m_opener = nullptr;
+void WebFrame::close() {
+  m_openedFrameTracker->dispose();
 }
 
 }  // namespace blink