[Reland] Make canceling Timers fast.

third_party/WebKit/public/platform/scheduler/base/task_queue.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 THIRD_PARTY_WEBKIT_PUBLIC_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_
 #define THIRD_PARTY_WEBKIT_PUBLIC_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 73 matching lines @@
       return *this;
     }
 
     const char* name;
     bool should_monitor_quiescence;
     TimeDomain* time_domain;
     bool should_notify_observers;
     bool should_report_when_execution_blocked;
   };
 
-  // Intended to be used as an opaque handle to a task posted by
-  // PostCancellableDelayedTask.
-  class BLINK_PLATFORM_EXPORT TaskHandle {
-   public:
-    TaskHandle();
-
-    // Returns false if the handle is equivalent to TaskHandle(), i.e. the
-    // handle doesn't represent a task that got posted.
-    operator bool() const;
-
-   private:
-    friend internal::TaskQueueImpl;
-    friend FakeWebTaskRunner;
-
-    // For immediate tasks.
-    TaskHandle(TaskQueue* task_queue, uint64_t enqueue_order);
-
-    // For delayed tasks.
-    TaskHandle(TaskQueue* task_queue,
-               base::TimeTicks scheduled_run_time,
-               int sequence_number);
-
-    uint64_t enqueue_order_;
-    base::TimeTicks scheduled_run_time_;
-#if DCHECK_IS_ON()
-    TaskQueue* task_queue_;
-#endif
-    int sequence_number_;
-  };
-
-  // Posts the given task to be run after |delay| has passed. Returns a handle
-  // which can be passed to CancelTask to cancel the task before it has run.
-  // NOTE this must be called on the thread this TaskQueue was created by.
-  virtual TaskHandle PostCancellableDelayedTask(
-      const tracked_objects::Location& from_here,
-      const base::Closure& task,
-      base::TimeDelta delay) = 0;
-
-  // Attempts to cancel a task posted by PostCancellableDelayedTask. Returns
-  // true on success or false otherwise. NOTE this must be called on the thread
-  // this TaskQueue was created by.
-  virtual bool CancelTask(const TaskHandle& handle) = 0;
-
   // Enable or disable task execution for this queue. NOTE this must be called
   // on the thread this TaskQueue was created by.
   virtual void SetQueueEnabled(bool enabled) = 0;
 
   // NOTE this must be called on the thread this TaskQueue was created by.
   virtual bool IsQueueEnabled() const = 0;
 
   // Returns true if the queue is completely empty.
   virtual bool IsEmpty() const = 0;
 
@@ skipping 47 matching lines @@
  protected:
   ~TaskQueue() override {}
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueue);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_PUBLIC_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_