replace 'virtual ... OVERRIDE' with '... override'

base/threading/worker_pool.cc

Index: base/threading/worker_pool.cc
diff --git a/base/threading/worker_pool.cc b/base/threading/worker_pool.cc
index 9e5e64c7f97d061d031dc0df678cc7df9a4f5e44..9a88bae3276a2636195e8871b0f77a7849109792 100644
--- a/base/threading/worker_pool.cc
+++ b/base/threading/worker_pool.cc
@@ -23,8 +23,8 @@ class PostTaskAndReplyWorkerPool : public internal::PostTaskAndReplyImpl {
   }
 
  private:
-  virtual bool PostTask(const tracked_objects::Location& from_here,
-                        const Closure& task) OVERRIDE {
+  bool PostTask(const tracked_objects::Location& from_here,
+                const Closure& task) override {
     return WorkerPool::PostTask(from_here, task, task_is_slow_);
   }
 
@@ -41,10 +41,10 @@ class WorkerPoolTaskRunner : public TaskRunner {
   explicit WorkerPoolTaskRunner(bool tasks_are_slow);
 
   // TaskRunner implementation
-  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
-                               const Closure& task,
-                               TimeDelta delay) OVERRIDE;
-  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
+  bool PostDelayedTask(const tracked_objects::Location& from_here,
+                       const Closure& task,
+                       TimeDelta delay) override;
+  bool RunsTasksOnCurrentThread() const override;
 
  private:
   virtual ~WorkerPoolTaskRunner();