Detach old frame on WebFrame::swap.

components/html_viewer/html_document.cc

 // 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 "components/html_viewer/html_document.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 237 matching lines @@
     blink::WebLocalFrame* parent,
     blink::WebTreeScopeType scope,
     const blink::WebString& frameName,
     blink::WebSandboxFlags sandboxFlags) {
   blink::WebLocalFrame* web_frame = blink::WebLocalFrame::create(scope, this);
   parent->appendChild(web_frame);
   return web_frame;
 }
 
 void HTMLDocument::frameDetached(blink::WebFrame* frame) {
+  frameDetached(frame, DetachType::Remove);
+}
+
+void HTMLDocument::frameDetached(blink::WebFrame* frame, DetachType type) {
+  DCHECK(type == DetachType::Remove);

[sky, 2015/06/02 23:01:40]

nit: DCHECK_EQ

   if (frame->parent())
     frame->parent()->removeChild(frame);
 
   // |frame| is invalid after here.
   frame->close();
 }
 
 blink::WebCookieJar* HTMLDocument::cookieJar(blink::WebLocalFrame* frame) {
   // TODO(darin): Blink does not fallback to the Platform provided WebCookieJar.
   // Either it should, as it once did, or we should find another solution here.
@@ skipping 82 matching lines @@
     touch_handler_->OnTouchEvent(*event);
     return;
   }
   scoped_ptr<blink::WebInputEvent> web_event =
       event.To<scoped_ptr<blink::WebInputEvent>>();
   if (web_event)
     web_view_->handleInputEvent(*web_event);
 }
 
 }  // namespace html_viewer