Standardize usage of virtual/override/final specifiers.

ash/accelerators/nested_accelerator_delegate.h

Index: ash/accelerators/nested_accelerator_delegate.h
diff --git a/ash/accelerators/nested_accelerator_delegate.h b/ash/accelerators/nested_accelerator_delegate.h
index 5a8dfadbd497bfa87326d1cf8b1a9a32d1ca0427..2e9b765b4924fbdecb59d23ae3855b5652fcbe33 100644
--- a/ash/accelerators/nested_accelerator_delegate.h
+++ b/ash/accelerators/nested_accelerator_delegate.h
@@ -13,11 +13,10 @@ namespace ash {
 class NestedAcceleratorDelegate : public wm::NestedAcceleratorDelegate {
  public:
   NestedAcceleratorDelegate();
-  virtual ~NestedAcceleratorDelegate();
+  ~NestedAcceleratorDelegate() override;
 
   // wm::AcceleratorDispatcher::Delegate
-  virtual Result ProcessAccelerator(
-      const ui::Accelerator& accelerator) override;
+  Result ProcessAccelerator(const ui::Accelerator& accelerator) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NestedAcceleratorDelegate);