Add support for HandleBlockingMessage to NaClMessageScanner

ppapi/tests/test_message_handler.h

Index: ppapi/tests/test_message_handler.h
diff --git a/ppapi/tests/test_message_handler.h b/ppapi/tests/test_message_handler.h
index 51d231741c0d877dcf3cd1b4a7702564c268c3fc..bbbc8fafa9b169666b99e89c6132ead35007ff78 100644
--- a/ppapi/tests/test_message_handler.h
+++ b/ppapi/tests/test_message_handler.h
@@ -26,6 +26,7 @@ class TestMessageHandler : public TestCase {
 
   std::string TestRegisterErrorConditions();
   std::string TestPostMessageAndAwaitResponse();
+  std::string TestArrayBuffer();
   std::string TestExceptions();
 
   // Wait for HandleMessage to be called, and return the Var it received.