Revert 212948 "Made MessagePump a non-thread safe class."

trunk/src/base/message_loop/incoming_task_queue.h

-// Copyright 2013 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.
-
-#ifndef BASE_MESSAGE_LOOP_INCOMING_TASK_QUEUE_H_
-#define BASE_MESSAGE_LOOP_INCOMING_TASK_QUEUE_H_
-
-#include "base/base_export.h"
-#include "base/memory/ref_counted.h"
-#include "base/pending_task.h"
-#include "base/synchronization/lock.h"
-#include "base/time/time.h"
-
-namespace base {
-
-class MessageLoop;
-class WaitableEvent;
-
-namespace internal {
-
-// Implements a queue of tasks posted to the message loop running on the current
-// thread. This class takes care of synchronizing posting tasks from different
-// threads and together with MessageLoop ensures clean shutdown.
-class BASE_EXPORT IncomingTaskQueue
-    : public RefCountedThreadSafe<IncomingTaskQueue> {
- public:
-  explicit IncomingTaskQueue(MessageLoop* message_loop);
-
-  // Appends a task to the incoming queue. Posting of all tasks is routed though
-  // AddToIncomingQueue() or TryAddToIncomingQueue() to make sure that posting
-  // task is properly synchronized between different threads.
-  //
-  // Returns true if the task was successfully added to the queue, otherwise
-  // returns false. In all cases, the ownership of |task| is transferred to the
-  // called method.
-  bool AddToIncomingQueue(const tracked_objects::Location& from_here,
-                          const Closure& task,
-                          TimeDelta delay,
-                          bool nestable);
-
-  // Same as AddToIncomingQueue() except that it will avoid blocking if the lock
-  // is already held, and will in that case (when the lock is contended) fail to
-  // add the task, and will return false.
-  bool TryAddToIncomingQueue(const tracked_objects::Location& from_here,
-                             const Closure& task);
-
-  // Returns true if the message loop has high resolution timers enabled.
-  // Provided for testing.
-  bool IsHighResolutionTimerEnabledForTesting();
-
-  // Returns true if the message loop is "idle". Provided for testing.
-  bool IsIdleForTesting();
-
-  // Takes the incoming queue lock, signals |caller_wait| and waits until
-  // |caller_signal| is signalled.
-  void LockWaitUnLockForTesting(WaitableEvent* caller_wait,
-                                WaitableEvent* caller_signal);
-
-  // Loads tasks from the |incoming_queue_| into |*work_queue|. Must be called
-  // from the thread that is running the loop.
-  void ReloadWorkQueue(TaskQueue* work_queue);
-
-  // Disconnects |this| from the parent message loop.
-  void WillDestroyCurrentMessageLoop();
-
- private:
-  friend class RefCountedThreadSafe<IncomingTaskQueue>;
-  virtual ~IncomingTaskQueue();
-
-  // Calculates the time at which a PendingTask should run.
-  TimeTicks CalculateDelayedRuntime(TimeDelta delay);
-
-  // Adds a task to |incoming_queue_|. The caller retains ownership of
-  // |pending_task|, but this function will reset the value of
-  // |pending_task->task|. This is needed to ensure that the posting call stack
-  // does not retain |pending_task->task| beyond this function call.
-  bool PostPendingTask(PendingTask* pending_task);
-
-#if defined(OS_WIN)
-  TimeTicks high_resolution_timer_expiration_;
-#endif
-
-  // The lock that protects access to |incoming_queue_|, |message_loop_| and
-  // |next_sequence_num_|.
-  base::Lock incoming_queue_lock_;
-
-  // An incoming queue of tasks that are acquired under a mutex for processing
-  // on this instance's thread. These tasks have not yet been been pushed to
-  // |message_loop_|.
-  TaskQueue incoming_queue_;
-
-  // Points to the message loop that owns |this|.
-  MessageLoop* message_loop_;
-
-  // The next sequence number to use for delayed tasks.
-  int next_sequence_num_;
-
-  DISALLOW_COPY_AND_ASSIGN(IncomingTaskQueue);
-};
-
-}  // namespace internal
-}  // namespace base
-
-#endif  // BASE_MESSAGE_LOOP_INCOMING_TASK_QUEUE_H_