Reland "Streamline frame detach"

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 "config.h"
 #include "public/web/WebFrame.h"
 
 #include "core/frame/RemoteFrame.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "platform/UserGestureIndicator.h"
@@ skipping 56 matching lines @@
         m_opener->m_openedFrameTracker->add(frame);
         swap(m_opener, frame->m_opener);
     }
     if (!m_openedFrameTracker->isEmpty()) {
         m_openedFrameTracker->updateOpener(frame);
         frame->m_openedFrameTracker.reset(m_openedFrameTracker.release());
     }
 
     // Finally, clone the state of the current Frame into one matching
     // the type of the passed in WebFrame.
-    // FIXME: This is a bit clunky; this results in pointless decrements and
-    // increments of connected subframes.
     FrameOwner* owner = oldFrame->owner();
-    oldFrame->disconnectOwnerElement();
-    if (frame->isWebLocalFrame()) {
+    if (frame->isWebLocalFrame())
         toWebLocalFrameImpl(frame)->initializeCoreFrame(oldFrame->host(), owner, oldFrame->tree().name(), nullAtom);
-    } else {
+    else
         toWebRemoteFrameImpl(frame)->initializeCoreFrame(oldFrame->host(), owner, oldFrame->tree().name());
-    }
 
     return true;
 }
 
 void WebFrame::detach()
 {
     toCoreFrame(this)->detach();
 }
 
 WebFrame* WebFrame::opener() const
@@ skipping 164 matching lines @@
 }
 
 void WebFrame::clearWeakFrames(Visitor* visitor)
 {
     if (!isFrameAlive(visitor, m_opener))
         m_opener = nullptr;
 }
 #endif
 
 } // namespace blink