Move the tracked completion callback code into shared impl.

ppapi/proxy/plugin_globals.h

Index: ppapi/proxy/plugin_globals.h
===================================================================
--- ppapi/proxy/plugin_globals.h	(revision 115831)
+++ ppapi/proxy/plugin_globals.h	(working copy)
@@ -9,6 +9,7 @@
 #include "ppapi/proxy/plugin_resource_tracker.h"
 #include "ppapi/proxy/plugin_var_tracker.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
+#include "ppapi/shared_impl/callback_tracker.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 
 namespace ppapi {
@@ -29,6 +30,8 @@
   // PpapiGlobals implementation.
   virtual ResourceTracker* GetResourceTracker() OVERRIDE;
   virtual VarTracker* GetVarTracker() OVERRIDE;
+  virtual CallbackTracker* GetCallbackTrackerForInstance(
+      PP_Instance instance) OVERRIDE;
   virtual FunctionGroupBase* GetFunctionAPI(PP_Instance inst,
                                             ApiID id) OVERRIDE;
   virtual PP_Module GetModuleForInstance(PP_Instance instance) OVERRIDE;
@@ -55,6 +58,7 @@
   PluginProxyDelegate* plugin_proxy_delegate_;
   PluginResourceTracker plugin_resource_tracker_;
   PluginVarTracker plugin_var_tracker_;
+  scoped_refptr<CallbackTracker> callback_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginGlobals);
 };