Use an explicit PID for duplicating Pepper handles rather than the Channel's.

ppapi/proxy/host_dispatcher.h

 // Copyright (c) 2012 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_HOST_DISPATCHER_H_
 #define PPAPI_PROXY_HOST_DISPATCHER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 40 matching lines @@
   HostDispatcher(PP_Module module,
                  PP_GetInterface_Func local_get_interface,
                  SyncMessageStatusReceiver* sync_status,
                  const PpapiPermissions& permissions);
   ~HostDispatcher();
 
   // You must call this function before anything else. Returns true on success.
   // The delegate pointer must outlive this class, ownership is not
   // transferred.
   virtual bool InitHostWithChannel(Delegate* delegate,
+                                   base::ProcessId peer_pid,
                                    const IPC::ChannelHandle& channel_handle,
                                    bool is_client,
                                    const Preferences& preferences);
 
   // The host side maintains a mapping from PP_Instance to Dispatcher so
   // that we can send the messages to the right channel.
   static HostDispatcher* GetForInstance(PP_Instance instance);
   static void SetForInstance(PP_Instance instance,
                              HostDispatcher* dispatcher);
   static void RemoveForInstance(PP_Instance instance);
@@ skipping 75 matching lines @@
  private:
   HostDispatcher* dispatcher_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedModuleReference);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_HOST_DISPATCHER_H_