Clean VM thread shutdown:

runtime/vm/message_handler.cc

 // Copyright (c) 2011, 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 "vm/message_handler.h"
 
 #include "vm/dart.h"
 #include "vm/lockers.h"
 #include "vm/port.h"
 #include "vm/thread_interrupter.h"
@@ skipping 103 matching lines @@
     }
 
     saved_priority = message->priority();
     if (message->IsOOB()) {
       oob_queue_->Enqueue(message, before_events);
     } else {
       queue_->Enqueue(message, before_events);
     }
     message = NULL;  // Do not access message.  May have been deleted.
 
-    if (pool_ != NULL && task_ == NULL) {
+    if ((pool_ != NULL) && (task_ == NULL)) {
       task_ = new MessageHandlerTask(this);
       pool_->Run(task_);
     }
   }
   // Invoke any custom message notification.
   MessageNotify(saved_priority);
 }
 
 
 Message* MessageHandler::DequeueMessage(Message::Priority min_priority) {
   // TODO(turnidge): Add assert that monitor_ is held here.
   Message* message = oob_queue_->Dequeue();
   if ((message == NULL) && (min_priority < Message::kOOBPriority)) {
     message = queue_->Dequeue();
   }
   return message;
 }
 
 
 bool MessageHandler::HandleMessages(bool allow_normal_messages,
                                     bool allow_multiple_normal_messages) {
   // If isolate() returns NULL StartIsolateScope does nothing.
   StartIsolateScope start_isolate(isolate());
 
-  // ThreadInterrupter may have gone to sleep waiting while waiting for
+  // ThreadInterrupter may have gone to sleep while waiting for
   // an isolate to start handling messages.
   ThreadInterrupter::WakeUp();
 
   // TODO(turnidge): Add assert that monitor_ is held here.
   bool result = true;
   Message::Priority min_priority = (allow_normal_messages && !paused()) ?
       Message::kNormalPriority : Message::kOOBPriority;
   Message* message = DequeueMessage(min_priority);
   while (message != NULL) {
     intptr_t message_len = message->len();
@@ skipping 211 matching lines @@
 
 
 void MessageHandler::AcquireQueues(AcquiredQueues* acquired_queues) {
   ASSERT(acquired_queues != NULL);
   // No double dipping.
   ASSERT(acquired_queues->handler_ == NULL);
   acquired_queues->Reset(this);
 }
 
 }  // namespace dart