Mojo: Add a "GetType()" to Dispatchers.

mojo/system/dispatcher_unittest.cc

Index: mojo/system/dispatcher_unittest.cc
diff --git a/mojo/system/dispatcher_unittest.cc b/mojo/system/dispatcher_unittest.cc
index 18ca4adfb2a56c510943ba89d8dc8dc94b3eef06..a54a902432dbbcd5e643dcc4b8351c737931b26a 100644
--- a/mojo/system/dispatcher_unittest.cc
+++ b/mojo/system/dispatcher_unittest.cc
@@ -21,6 +21,10 @@ class TrivialDispatcher : public Dispatcher {
  public:
   TrivialDispatcher() {}
 
+  virtual Type GetType() OVERRIDE {
+    return kTypeUnknown;
+  }
+
  private:
   friend class base::RefCountedThreadSafe<TrivialDispatcher>;
   virtual ~TrivialDispatcher() {}
@@ -36,6 +40,8 @@ class TrivialDispatcher : public Dispatcher {
 TEST(DispatcherTest, Basic) {
   scoped_refptr<Dispatcher> d(new TrivialDispatcher());
 
+  EXPECT_EQ(Dispatcher::kTypeUnknown, d->GetType());
+
   EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
             d->WriteMessage(NULL, 0, NULL, MOJO_WRITE_MESSAGE_FLAG_NONE));
   EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,