Add //mojo/edk/platform and move platform_task_runners.h there.

mojo/edk/system/master_connection_manager.cc

 // Copyright 2015 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/master_connection_manager.h"
 
 #include <memory>
 #include <unordered_map>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "mojo/edk/embedder/master_process_delegate.h"
 #include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/embedder/platform_handle.h"
 #include "mojo/edk/embedder/platform_handle_vector.h"
 #include "mojo/edk/system/connection_manager_messages.h"
 #include "mojo/edk/system/message_in_transit.h"
 #include "mojo/edk/system/raw_channel.h"
 #include "mojo/edk/system/transport_data.h"
 #include "mojo/edk/util/make_unique.h"
 #include "mojo/edk/util/waitable_event.h"
 #include "mojo/public/cpp/system/macros.h"
 
+using mojo::platform::TaskRunner;
 using mojo::util::AutoResetWaitableEvent;
 using mojo::util::MutexLocker;
 using mojo::util::RefPtr;
 
 namespace mojo {
 namespace system {
 
 namespace {
 
 const ProcessIdentifier kFirstSlaveProcessIdentifier = 2;
@@ skipping 297 matching lines @@
 
 MasterConnectionManager::~MasterConnectionManager() {
   DCHECK(!delegate_thread_task_runner_);
   DCHECK(!master_process_delegate_);
   DCHECK(!private_thread_.message_loop());
   DCHECK(helpers_.empty());
   DCHECK(pending_connects_.empty());
 }
 
 void MasterConnectionManager::Init(
-    RefPtr<embedder::PlatformTaskRunner>&& delegate_thread_task_runner,
+    RefPtr<TaskRunner>&& delegate_thread_task_runner,
     embedder::MasterProcessDelegate* master_process_delegate) {
   DCHECK(delegate_thread_task_runner);
   DCHECK(master_process_delegate);
   DCHECK(!delegate_thread_task_runner_);
   DCHECK(!master_process_delegate_);
   DCHECK(!private_thread_.message_loop());
 
   delegate_thread_task_runner_ = std::move(delegate_thread_task_runner);
   master_process_delegate_ = master_process_delegate;
   CHECK(private_thread_.StartWithOptions(
@@ skipping 385 matching lines @@
 }
 
 void MasterConnectionManager::AssertOnPrivateThread() const {
   // This should only be called after |Init()| and before |Shutdown()|.
   DCHECK(private_thread_.message_loop());
   DCHECK_EQ(base::MessageLoop::current(), private_thread_.message_loop());
 }
 
 }  // namespace system
 }  // namespace mojo