Add ability to clear pending tasks of TestMockTimeTaskRunner without running the tasks.

base/test/test_mock_time_task_runner.h

 // 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.
 
 #ifndef BASE_TEST_TEST_MOCK_TIME_TASK_RUNNER_H_
 #define BASE_TEST_TEST_MOCK_TIME_TASK_RUNNER_H_
 
 #include <queue>
 #include <vector>
 
@@ skipping 43 matching lines @@
   void FastForwardBy(TimeDelta delta);
 
   // Fast-forwards virtual time just until all tasks are executed.
   void FastForwardUntilNoTasksRemain();
 
   // Executes all tasks that have no remaining delay. Tasks with a remaining
   // delay greater than zero will remain enqueued, and no virtual time will
   // elapse.
   void RunUntilIdle();
 
+  // Clears the queue of pending tasks without running them.
+  void ClearPendingTasks();
+
   // Returns the current virtual time (initially starting at the Unix epoch).
   Time Now() const;
 
   // Returns the current virtual tick time (initially starting at 0).
   TimeTicks NowTicks() const;
 
   // Returns a Clock that uses the virtual time of |this| as its time source.
   // The returned Clock will hold a reference to |this|.
   scoped_ptr<Clock> GetMockClock() const;
 
@@ skipping 67 matching lines @@
   // |tasks_lock_| is held.
   TaskPriorityQueue tasks_;
   Lock tasks_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(TestMockTimeTaskRunner);
 };
 
 }  // namespace base
 
 #endif  // BASE_TEST_TEST_MOCK_TIME_TASK_RUNNER_H_