Never lock the Pepper proxy lock on the IO thread

ppapi/proxy/plugin_globals.h

Index: ppapi/proxy/plugin_globals.h
diff --git a/ppapi/proxy/plugin_globals.h b/ppapi/proxy/plugin_globals.h
index 2aaf15770ac12424574961a16d9421bdb383e223..ed93009be351e9f360f0600f23fe3a1cf940cb22 100644
--- a/ppapi/proxy/plugin_globals.h
+++ b/ppapi/proxy/plugin_globals.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_local_storage.h"
 #include "ppapi/proxy/connection.h"
@@ -33,8 +34,10 @@ struct Preferences;
 namespace proxy {
 
 class MessageLoopResource;
+class PluginMessageFilter;
 class PluginProxyDelegate;
 class ResourceReplyThreadRegistrar;
+class UDPSocketFilter;
 
 class PPAPI_PROXY_EXPORT PluginGlobals : public PpapiGlobals {
  public:
@@ -136,6 +139,14 @@ class PPAPI_PROXY_EXPORT PluginGlobals : public PpapiGlobals {
     return resource_reply_thread_registrar_.get();
   }
 
+  UDPSocketFilter* udp_socket_filter() const {
+    return udp_socket_filter_.get();
+  }
+  // Add any necessary ResourceMessageFilters to the PluginMessageFilter so
+  // that they can receive and handle appropriate messages on the IO thread.
+  void RegisterResourceMessageFilters(
+      ppapi::proxy::PluginMessageFilter* plugin_filter);
+
   // Interval to limit how many IPC messages are sent indicating that the plugin
   // is active and should be kept alive. The value must be smaller than any
   // threshold used to kill inactive plugins by the embedder host.
@@ -178,6 +189,8 @@ class PPAPI_PROXY_EXPORT PluginGlobals : public PpapiGlobals {
 
   scoped_refptr<ResourceReplyThreadRegistrar> resource_reply_thread_registrar_;
 
+  scoped_refptr<UDPSocketFilter> udp_socket_filter_;
+
   // Indicates activity by the plugin. Used to monitor when a plugin can be
   // shutdown due to idleness. Current needs do not require differentiating
   // between idle state between multiple instances, if any are active they are