Support sync mojo IPCs to and from bindings running on a sequence.

mojo/public/cpp/bindings/tests/report_bad_message_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "mojo/edk/embedder/embedder.h"
@@ skipping 70 matching lines @@
   void SetErrorHandler(const base::Closure& handler) {
     error_handler_ = handler;
   }
 
  private:
   void OnProcessError(const std::string& error) {
     if (!error_handler_.is_null())
       error_handler_.Run();
   }
 
+  base::MessageLoop message_loop;
   TestBadMessagesPtr proxy_;
   TestBadMessagesImpl impl_;
   base::Closure error_handler_;
-  base::MessageLoop message_loop;
 };
 
 TEST_F(ReportBadMessageTest, Request) {
   // Verify that basic immediate error reporting works.
   bool error = false;
   SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
   EXPECT_TRUE(proxy()->RejectSync());
   EXPECT_TRUE(error);
 }
 
@@ skipping 80 matching lines @@
   }
 
   EXPECT_FALSE(error);
   bad_message_callback.Run("nope nope nope");
   EXPECT_TRUE(error);
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace mojo