Add MutexLocker and MonitorLocker to platform/bin

runtime/bin/thread_pool.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/thread_pool.h"
 
+#include "bin/thread.h"
+
 void TaskQueue::Insert(TaskQueueEntry* entry) {
+  MonitorLocker monitor(&monitor_);
   monitor_.Enter();
   if (head_ == NULL) {
     head_ = entry;
     tail_ = entry;
-    monitor_.Notify();
+    monitor.Notify();
   } else {
     tail_->set_next(entry);
     tail_ = entry;
   }
-  monitor_.Exit();
 }
 
 
 TaskQueueEntry* TaskQueue::Remove() {
-  monitor_.Enter();
+  MonitorLocker monitor(&monitor_);
   TaskQueueEntry* result = head_;
   while (result == NULL) {
     if (terminate_) {
-      monitor_.Exit();
       return NULL;
     }
-    monitor_.Wait(dart::Monitor::kNoTimeout);
+    monitor.Wait();
     if (terminate_) {
-      monitor_.Exit();
       return NULL;
     }
     result = head_;
   }
   head_ = result->next();
   ASSERT(head_ != NULL || tail_ == result);
-  monitor_.Exit();
   return result;
 }
 
 
 void TaskQueue::Shutdown() {
-  monitor_.Enter();
+  MonitorLocker monitor(&monitor_);
   terminate_ = true;
-  monitor_.NotifyAll();
-  monitor_.Exit();
+  monitor.NotifyAll();
 }
 
 
 void ThreadPool::InsertTask(Task task) {
   TaskQueueEntry* entry = new TaskQueueEntry(task);
   queue_.Insert(entry);
 }
 
 
 Task ThreadPool::WaitForTask() {
@@ skipping 15 matching lines @@
   while (!pool->terminate_) {
     if (Dart_IsVMFlagSet("trace_thread_pool")) {
       printf("Waiting for task\n");
     }
     Task task = pool->WaitForTask();
     if (pool->terminate_) return NULL;
     (*(pool->task_handler_))(task);
   }
   return NULL;
 };