Never lock the Pepper proxy lock on the IO thread

ppapi/proxy/resource_reply_thread_registrar.h

 // 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.
 
 #ifndef PPAPI_PROXY_RESOURCE_REPLY_THREAD_REGISTRAR_H_
 #define PPAPI_PROXY_RESOURCE_REPLY_THREAD_REGISTRAR_H_
 
 #include <map>
 #include <set>
 
@@ skipping 29 matching lines @@
   explicit ResourceReplyThreadRegistrar(
       scoped_refptr<base::MessageLoopProxy> main_thread);
 
   // This method can only be called while holding the Pepper proxy lock; the
   // other methods can be called with/without the Pepper proxy lock.
   void Register(PP_Resource resource,
                 int32_t sequence_number,
                 scoped_refptr<TrackedCallback> reply_thread_hint);
   void Unregister(PP_Resource resource);
 
-  // This results in Resource::OnReplyReceived() for the specified message type
-  // to be called on the IO thread directly, while holding the Pepper proxy
-  // lock.
-  void HandleOnIOThread(uint32 nested_msg_type);
-
-  // This method returns NULL if the target thread is the IO thread (because
-  // that is the thread on which this method is supposed to be called).
   scoped_refptr<base::MessageLoopProxy> GetTargetThread(
       const ResourceMessageReplyParams& reply_params,
       const IPC::Message& nested_msg);
 
  private:
   friend class base::RefCountedThreadSafe<ResourceReplyThreadRegistrar>;
 
   typedef std::map<int32_t, scoped_refptr<base::MessageLoopProxy> >
       SequenceThreadMap;
   typedef std::map<PP_Resource, SequenceThreadMap> ResourceMap;
 
   ~ResourceReplyThreadRegistrar();
 
   // The lock that protects the data members below.
   // Please note that we should never try to acquire the Pepper proxy lock while
   // holding |lock_|, otherwise we will cause deadlock.
   base::Lock lock_;
   ResourceMap map_;
-  std::set<uint32> io_thread_message_types_;
   scoped_refptr<base::MessageLoopProxy> main_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceReplyThreadRegistrar);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif   // PPAPI_PROXY_RESOURCE_REPLY_THREAD_REGISTRAR_H_