Standardize usage of virtual/override/final specifiers.

chrome/browser/ui/ash/accessibility/ax_tree_source_ash_unittest.cc

Index: chrome/browser/ui/ash/accessibility/ax_tree_source_ash_unittest.cc
diff --git a/chrome/browser/ui/ash/accessibility/ax_tree_source_ash_unittest.cc b/chrome/browser/ui/ash/accessibility/ax_tree_source_ash_unittest.cc
index 7931b051ca8d1525ec17a79b29c7b552b5e97146..2b42f5c4dc5b0cfb17ebb646e85da9ea37e5c054 100644
--- a/chrome/browser/ui/ash/accessibility/ax_tree_source_ash_unittest.cc
+++ b/chrome/browser/ui/ash/accessibility/ax_tree_source_ash_unittest.cc
@@ -42,9 +42,9 @@ size_t GetSize(AXAuraObjWrapper* tree) {
 class AXTreeSourceAshTest : public ash::test::AshTestBase {
  public:
   AXTreeSourceAshTest() {}
-  virtual ~AXTreeSourceAshTest() {}
+  ~AXTreeSourceAshTest() override {}
 
-  virtual void SetUp() override {
+  void SetUp() override {
     AshTestBase::SetUp();
 
     widget_ = new Widget();