Make much of the proxy thread-safe with 1 great big lock.

ppapi/proxy/ppb_core_proxy.cc

Index: ppapi/proxy/ppb_core_proxy.cc
diff --git a/ppapi/proxy/ppb_core_proxy.cc b/ppapi/proxy/ppb_core_proxy.cc
index 7e8724101614900d279319f00a0e1d69845b604a..9173df65dd69b429926eb4169b26ece53def1c55 100644
--- a/ppapi/proxy/ppb_core_proxy.cc
+++ b/ppapi/proxy/ppb_core_proxy.cc
@@ -18,6 +18,7 @@
 #include "ppapi/proxy/plugin_dispatcher.h"
 #include "ppapi/proxy/plugin_resource_tracker.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/shared_impl/proxy_lock.h"
 #include "ppapi/shared_impl/time_conversion.h"
 
 namespace ppapi {
@@ -32,10 +33,12 @@ base::MessageLoopProxy* GetMainThreadMessageLoop() {
 }
 
 void AddRefResource(PP_Resource resource) {
+  ppapi::ProxyAutoLock lock;
   PluginResourceTracker::GetInstance()->AddRefResource(resource);
 }
 
 void ReleaseResource(PP_Resource resource) {
+  ppapi::ProxyAutoLock lock;
   PluginResourceTracker::GetInstance()->ReleaseResource(resource);
 }