[WIP] Add DCHECK for mojo::edk::Init().

mash/test/mash_unittests.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/test/launcher/unit_test_launcher.h"
+#include "base/test/test_io_thread.h"
 #include "mash/test/mash_test_suite.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "mojo/edk/test/scoped_ipc_support.h"
 
 int MasterProcessMain(int argc, char** argv) {
   mash::test::MashTestSuite test_suite(argc, argv);
 
+  mojo::edk::Init();
+  base::TestIOThread test_io_thread(base::TestIOThread::kAutoStart);
+  mojo::edk::test::ScopedIPCSupport ipc_support(test_io_thread.task_runner());
+
   return base::LaunchUnitTests(argc, argv,
                                base::Bind(&mash::test::MashTestSuite::Run,
                                           base::Unretained(&test_suite)));
 }