Mojo C++ bindings: sync call support for associated interfaces and master interfaces

mojo/public/interfaces/bindings/tests/test_sync_methods.mojom

 // 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.
 
 module mojo.test;
 
 interface TestSyncCodeGeneration {
   [Sync]
   NoInput() => (int32 result);
 
   [Sync]
   NoOutput(int32 value) => ();
 
   [Sync]
   NoInOut() => ();
 
   [Sync]
   HaveInOut(int32 value1, int32 value2) => (int32 result1, int32 result2);
 };
 
 interface TestSync {
   [Sync]
   Ping() => ();
 
   [Sync]
   Echo(int32 value) => (int32 result);
 
   AsyncEcho(int32 value) => (int32 result);
 };
+
+interface TestSyncMaster {
+  [Sync]
+  Ping() => ();
+
+  [Sync]
+  Echo(int32 value) => (int32 result);
+
+  AsyncEcho(int32 value) => (int32 result);
+
+  SendInterface(associated TestSync ptr);
+};