Refactor frame detach to work for both local and remote frames.

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 "core/frame/RemoteFrameView.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 
 namespace blink {
 
 inline RemoteFrame::RemoteFrame(FrameClient* client, FrameHost* host, FrameOwner* owner)
     : Frame(client, host, owner)
 {
 }
 
 PassRefPtr<RemoteFrame> RemoteFrame::create(FrameClient* client, FrameHost* host, FrameOwner* owner)
 {
     RefPtr<RemoteFrame> frame = adoptRef(new RemoteFrame(client, host, owner));
     return frame.release();
 }
 
 RemoteFrame::~RemoteFrame()
 {
     setView(nullptr);
 }
 
+void RemoteFrame::detach()
+{
+    detachChildren();
+    m_host = 0;
+}
+
 void RemoteFrame::setView(PassRefPtr<RemoteFrameView> view)
 {
     m_view = view;
 }
 
 void RemoteFrame::createView()
 {
     RefPtr<RemoteFrameView> view = RemoteFrameView::create(this);
     setView(view);
 
     if (ownerRenderer()) {
         HTMLFrameOwnerElement* owner = deprecatedLocalOwner();
         ASSERT(owner);
         owner->setWidget(view);
     }
 }
 
 } // namespace blink