Move scoped_test_dir.* and test_io_thread.* from edk/test to edk/system/test.

mojo/edk/system/message_pipe_test_utils.cc

 // Copyright 2014 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 "mojo/edk/system/message_pipe_test_utils.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "mojo/edk/system/channel.h"
@@ skipping 20 matching lines @@
                                                       : add_result;
   }
 
   MojoResult wait_result = waiter.Wait(MOJO_DEADLINE_INDEFINITE, nullptr);
   mp->RemoveAwakable(0, &waiter, signals_state);
   return wait_result;
 }
 
 ChannelThread::ChannelThread(embedder::PlatformSupport* platform_support)
     : platform_support_(platform_support),
-      test_io_thread_(mojo::test::TestIOThread::StartMode::MANUAL) {}
+      test_io_thread_(TestIOThread::StartMode::MANUAL) {}
 
 ChannelThread::~ChannelThread() {
   Stop();
 }
 
 void ChannelThread::Start(embedder::ScopedPlatformHandle platform_handle,
                           RefPtr<ChannelEndpoint>&& channel_endpoint) {
   test_io_thread_.Start();
   test_io_thread_.PostTaskAndWait(
       base::Bind(&ChannelThread::InitChannelOnIOThread, base::Unretained(this),
@@ skipping 49 matching lines @@
 }
 
 void MultiprocessMessagePipeTestBase::Init(RefPtr<ChannelEndpoint>&& ep) {
   channel_thread_.Start(helper_.server_platform_handle.Pass(), std::move(ep));
 }
 #endif
 
 }  // namespace test
 }  // namespace system
 }  // namespace mojo