Integrating Mac OS Grammar checker into Chromium.

chrome/renderer/render_view_observer.cc

 // Copyright (c) 2011 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 "chrome/renderer/render_view_observer.h"
 
 #include "chrome/renderer/render_view.h"
 
 RenderViewObserver::RenderViewObserver(RenderView* render_view)
-    : render_view_(render_view), routing_id_(render_view->routing_id()) {
-  render_view_->AddObserver(this);
+    : render_view_(render_view),
+      routing_id_(render_view ? render_view->routing_id() : 0) {
+  // |render_view| can be NULL on unit testing.
+  if (render_view_)
+    render_view_->AddObserver(this);
 }
 
 RenderViewObserver::~RenderViewObserver() {
   if (render_view_)
     render_view_->RemoveObserver(this);
 }
 
 void RenderViewObserver::OnDestruct() {
   delete this;
 }
 
 bool RenderViewObserver::OnMessageReceived(const IPC::Message& message) {
   return false;
 }
 
 bool RenderViewObserver::Send(IPC::Message* message) {
   if (render_view_)
     return render_view_->Send(message);
 
   delete message;
   return false;
 }