PPAPI: Add unlocking for PPP calls and callbacks. Add more locking.

ppapi/proxy/ppp_graphics_3d_proxy.cc

Index: ppapi/proxy/ppp_graphics_3d_proxy.cc
diff --git a/ppapi/proxy/ppp_graphics_3d_proxy.cc b/ppapi/proxy/ppp_graphics_3d_proxy.cc
index d83aa80e6109a635384cfe45aa064a44663d3174..fd56feb6edba67e88c174707c4314b817323f041 100644
--- a/ppapi/proxy/ppp_graphics_3d_proxy.cc
+++ b/ppapi/proxy/ppp_graphics_3d_proxy.cc
@@ -8,6 +8,7 @@
 #include "ppapi/proxy/host_dispatcher.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/shared_impl/proxy_lock.h"
 
 namespace ppapi {
 namespace proxy {
@@ -65,7 +66,7 @@ bool PPP_Graphics3D_Proxy::OnMessageReceived(const IPC::Message& msg) {
 
 void PPP_Graphics3D_Proxy::OnMsgContextLost(PP_Instance instance) {
   if (ppp_graphics_3d_impl_)
-    ppp_graphics_3d_impl_->Graphics3DContextLost(instance);
+    CallWhileUnlocked(ppp_graphics_3d_impl_->Graphics3DContextLost, instance);
 }
 
 }  // namespace proxy