[Reland] Make canceling Timers fast.

third_party/WebKit/Source/platform/scheduler/child/compositor_worker_scheduler.cc

Index: third_party/WebKit/Source/platform/scheduler/child/compositor_worker_scheduler.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/child/compositor_worker_scheduler.cc b/third_party/WebKit/Source/platform/scheduler/child/compositor_worker_scheduler.cc
index 0c654ee77e942a618665fac72a4d39af8ac30af4..ca810dd885da699d5f95bf62d198d836bc44dee7 100644
--- a/third_party/WebKit/Source/platform/scheduler/child/compositor_worker_scheduler.cc
+++ b/third_party/WebKit/Source/platform/scheduler/child/compositor_worker_scheduler.cc
@@ -25,24 +25,6 @@ class CompositorWorkerTaskRunnerWrapper : public TaskQueue {
     return task_runner_->RunsTasksOnCurrentThread();
   }
 
-  TaskQueue::TaskHandle PostCancellableDelayedTask(
-      const tracked_objects::Location& from_here,
-      const base::Closure& task,
-      base::TimeDelta delay) {
-    NOTREACHED();
-    return TaskHandle();
-  }
-
-  bool CancelTask(const TaskQueue::TaskHandle& handle) {
-    NOTREACHED();
-    return false;
-  }
-
-  bool IsTaskPending(const TaskQueue::TaskHandle& handle) const {
-    NOTREACHED();
-    return false;
-  }
-
   bool PostDelayedTask(const tracked_objects::Location& from_here,
                        const base::Closure& task,
                        base::TimeDelta delay) override {