Fix for the revert of r172659. The problem was that MediaStreamImpl's constructor was getting a Ren…

content/public/renderer/render_frame_observer.cc

 // Copyright 2013 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 "content/public/renderer/render_frame_observer.h"
 
 #include "content/renderer/render_frame_impl.h"
 
 using blink::WebFrame;
 
 namespace content {
 
 RenderFrameObserver::RenderFrameObserver(RenderFrame* render_frame)
     : render_frame_(render_frame),
       routing_id_(MSG_ROUTING_NONE) {
   // |render_frame| can be NULL on unit testing.
   if (render_frame) {
     RenderFrameImpl* impl = static_cast<RenderFrameImpl*>(render_frame);
     routing_id_ = impl->GetRoutingID();
+    DCHECK_NE(routing_id_, MSG_ROUTING_NONE);
     impl->AddObserver(this);
   }
 }
 
 RenderFrameObserver::~RenderFrameObserver() {
   if (render_frame_) {
     RenderFrameImpl* impl = static_cast<RenderFrameImpl*>(render_frame_);
     impl->RemoveObserver(this);
   }
 }
@@ skipping 16 matching lines @@
 
 RenderFrame* RenderFrameObserver::render_frame() const {
   return render_frame_;
 }
 
 void RenderFrameObserver::RenderFrameGone() {
   render_frame_ = NULL;
 }
 
 }  // namespace content