Support using TrackedCallbacks as hints to determine the handling thread of resource reply messages

content/ppapi_plugin/ppapi_thread.cc

Index: content/ppapi_plugin/ppapi_thread.cc
diff --git a/content/ppapi_plugin/ppapi_thread.cc b/content/ppapi_plugin/ppapi_thread.cc
index a29a63903b4e7e36cf57bd3f1ad87d7d1edb2d61..1040e252e956ff29f04c534cdaf8cad3d8d21852 100644
--- a/content/ppapi_plugin/ppapi_thread.cc
+++ b/content/ppapi_plugin/ppapi_thread.cc
@@ -36,7 +36,9 @@
 #include "ppapi/c/ppp.h"
 #include "ppapi/proxy/interface_list.h"
 #include "ppapi/proxy/plugin_globals.h"
+#include "ppapi/proxy/plugin_message_filter.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/proxy/resource_reply_thread_registrar.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "third_party/WebKit/public/web/WebKit.h"
 #include "ui/base/ui_base_switches.h"
@@ -103,6 +105,12 @@ PpapiThread::PpapiThread(const CommandLine& command_line, bool is_broker)
   // note that only those InterfaceProxy-based ones require registration.
   AddRoute(ppapi::API_ID_PPB_HOSTRESOLVER_PRIVATE,
            &dispatcher_message_listener_);
+
+  if (!is_broker_) {
+    channel()->AddFilter(
+        new ppapi::proxy::PluginMessageFilter(
+            NULL, globals->resource_reply_thread_registrar()));
+  }
 }
 
 PpapiThread::~PpapiThread() {
@@ -135,7 +143,6 @@ bool PpapiThread::OnControlMessageReceived(const IPC::Message& msg) {
     IPC_MESSAGE_HANDLER(PpapiMsg_SetNetworkState, OnSetNetworkState)
     IPC_MESSAGE_HANDLER(PpapiMsg_Crash, OnCrash)
     IPC_MESSAGE_HANDLER(PpapiMsg_Hang, OnHang)
-    IPC_MESSAGE_HANDLER(PpapiPluginMsg_ResourceReply, OnResourceReply)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -386,13 +393,6 @@ void PpapiThread::OnCreateChannel(base::ProcessId renderer_pid,
   Send(new PpapiHostMsg_ChannelCreated(channel_handle));
 }
 
-void PpapiThread::OnResourceReply(
-    const ppapi::proxy::ResourceMessageReplyParams& reply_params,
-    const IPC::Message& nested_msg) {
-  ppapi::proxy::PluginDispatcher::DispatchResourceReply(reply_params,
-                                                        nested_msg);
-}
-
 void PpapiThread::OnSetNetworkState(bool online) {
   // Note the browser-process side shouldn't send us these messages in the
   // first unless the plugin has dev permissions, so we don't need to check