Standardize usage of virtual/override/final specifiers.

ash/wm/event_client_impl.h

Index: ash/wm/event_client_impl.h
diff --git a/ash/wm/event_client_impl.h b/ash/wm/event_client_impl.h
index 5f652723033e892869e94a11e0ce62e07fdc603b..8a7a488a883af4985c74c251e33c4021f6b6e686 100644
--- a/ash/wm/event_client_impl.h
+++ b/ash/wm/event_client_impl.h
@@ -15,13 +15,12 @@ namespace ash {
 class EventClientImpl : public aura::client::EventClient {
  public:
   EventClientImpl();
-  virtual ~EventClientImpl();
+  ~EventClientImpl() override;
 
  private:
   // Overridden from aura::client::EventClient:
-  virtual bool CanProcessEventsWithinSubtree(
-      const aura::Window* window) const override;
-  virtual ui::EventTarget* GetToplevelEventTarget() override;
+  bool CanProcessEventsWithinSubtree(const aura::Window* window) const override;
+  ui::EventTarget* GetToplevelEventTarget() override;
 
   DISALLOW_COPY_AND_ASSIGN(EventClientImpl);
 };