Change the DidChangeView update to take a new ViewChanged resource.

chrome/browser/nacl_host/nacl_process_host.h

 // 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.
 
 #ifndef CHROME_BROWSER_NACL_HOST_NACL_PROCESS_HOST_H_
 #define CHROME_BROWSER_NACL_HOST_NACL_PROCESS_HOST_H_
 #pragma once
 
 #include "build/build_config.h"
 
@@ skipping 13 matching lines @@
 // After that, most of the communication is directly between NaCl plugin
 // running in the renderer and NaCl processes.
 class NaClProcessHost : public BrowserChildProcessHost {
  public:
   explicit NaClProcessHost(const std::wstring& url);
   virtual ~NaClProcessHost();
 
   // Do any minimal work that must be done at browser startup.
   static void EarlyStartup();
 
-  // Initialize the new NaCl process, returning true on success.
+  // Initialize the new NaCl process, returning true on success. On success,
+  // the NaCl process host will assume responsibility for sending the reply
+  // message. On failure, the reply will not be sent and this is the caller's
+  // responsibility to avoid handling the renderer.

[dmichael (off chromium), 2011/12/20 19:01:34]

"avoid handling the renderer"? Is it supposed to say "hanging" or something?

   bool Launch(ChromeRenderMessageFilter* chrome_render_message_filter,
               int socket_count,
               IPC::Message* reply_msg);
 
   virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
 
   void OnProcessLaunchedByBroker(base::ProcessHandle handle);
 
  protected:
   virtual void OnProcessCrashed(int exit_code) OVERRIDE;
@@ skipping 10 matching lines @@
   virtual void OnProcessLaunched() OVERRIDE;
 
   void IrtReady();
   void SendStart(base::PlatformFile irt_file);
 
  private:
   // The ChromeRenderMessageFilter that requested this NaCl process.  We use
   // this for sending the reply once the process has started.
   scoped_refptr<ChromeRenderMessageFilter> chrome_render_message_filter_;
 
-  // The reply message to send.
+  // The reply message to send. We must always send this message when the
+  // sub-process either succeeds or fails to unblock the renderer waiting for
+  // the reply. NULL when there is no reply to send.
   IPC::Message* reply_msg_;
 
   // Socket pairs for the NaCl process and renderer.
   scoped_ptr<NaClInternal> internal_;
 
   base::WeakPtrFactory<NaClProcessHost> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NaClProcessHost);
 };
 
 #endif  // CHROME_BROWSER_NACL_HOST_NACL_PROCESS_HOST_H_