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/FrameHost.h"
 #include "core/frame/RemoteFrame.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/heap/Handle.h"
 #include "web/OpenedFrameTracker.h"
 #include "web/WebLocalFrameImpl.h"
 #include "web/WebRemoteFrameImpl.h"
 #include <algorithm>
 
 namespace blink {
@@ skipping 97 matching lines @@
     m_lastChild = child;
 
     if (oldLast) {
         child->m_previousSibling = oldLast;
         oldLast->m_nextSibling = child;
     } else {
         m_firstChild = child;
     }
 
     toCoreFrame(this)->tree().invalidateScopedChildCount();
+    toCoreFrame(this)->host()->incrementSubframeCount();
 }
 
 void WebFrame::removeChild(WebFrame* child)
 {
     child->m_parent = 0;
 
     if (m_firstChild == child)
         m_firstChild = child->m_nextSibling;
     else
         child->m_previousSibling->m_nextSibling = child->m_nextSibling;
 
     if (m_lastChild == child)
         m_lastChild = child->m_previousSibling;
     else
         child->m_nextSibling->m_previousSibling = child->m_previousSibling;
 
     child->m_previousSibling = child->m_nextSibling = 0;
 
     toCoreFrame(this)->tree().invalidateScopedChildCount();
+    toCoreFrame(this)->host()->decrementSubframeCount();
 }
 
 WebFrame* WebFrame::parent() const
 {
     return m_parent;
 }
 
 WebFrame* WebFrame::top() const
 {
     WebFrame* frame = const_cast<WebFrame*>(this);
@@ skipping 106 matching lines @@
 }
 
 void WebFrame::clearWeakFrames(Visitor* visitor)
 {
     if (!isFrameAlive(visitor, m_opener))
         m_opener = nullptr;
 }
 #endif
 
 } // namespace blink