PPAPI: Disallow blocking callbacks while handling a blocking message

mojo/examples/pepper_container_app/mojo_ppapi_globals.cc

Index: mojo/examples/pepper_container_app/mojo_ppapi_globals.cc
diff --git a/mojo/examples/pepper_container_app/mojo_ppapi_globals.cc b/mojo/examples/pepper_container_app/mojo_ppapi_globals.cc
index aaf9b0a7ba1ca5083422777827126d6dc1f7592b..a98ddc776f438bd9d7970125bbf3ddd7ef51a49e 100644
--- a/mojo/examples/pepper_container_app/mojo_ppapi_globals.cc
+++ b/mojo/examples/pepper_container_app/mojo_ppapi_globals.cc
@@ -44,6 +44,10 @@ class MojoPpapiGlobals::MainThreadMessageLoopResource
     return main_thread_message_loop_.get();
   }
 
+  virtual bool CurrentlyHandlingBlockingMessage() OVERRIDE {
+    return false;
+  }
+
   // ppapi::thunk::PPB_MessageLoop_API implementation.
   virtual int32_t AttachToCurrentThread() OVERRIDE {
     NOTIMPLEMENTED();