Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 141 matching lines @@
     return nullptr;
   return ToLayoutPart(GetLayoutObject());
 }
 
 void HTMLFrameOwnerElement::SetContentFrame(Frame& frame) {
   // Make sure we will not end up with two frames referencing the same owner
   // element.
   DCHECK(!content_frame_ || content_frame_->Owner() != this);
   // Disconnected frames should not be allowed to load.
   DCHECK(isConnected());
+
   content_frame_ = &frame;
 
   for (ContainerNode* node = this; node; node = node->ParentOrShadowHostNode())
     node->IncrementConnectedSubframeCount();
 }
 
 void HTMLFrameOwnerElement::ClearContentFrame() {
   if (!content_frame_)
     return;
 
@@ skipping 170 matching lines @@
 }
 
 DEFINE_TRACE(HTMLFrameOwnerElement) {
   visitor->Trace(content_frame_);
   visitor->Trace(widget_);
   HTMLElement::Trace(visitor);
   FrameOwner::Trace(visitor);
 }
 
 }  // namespace blink