Standardize usage of virtual/override/final specifiers.

ui/views/examples/single_split_view_example.cc

Index: ui/views/examples/single_split_view_example.cc
diff --git a/ui/views/examples/single_split_view_example.cc b/ui/views/examples/single_split_view_example.cc
index 21dd88e835e1cb1cd39fe9cb66bbce42d88135df..1824ccc6c64dc88b344b01db4c5c5760a7b77add 100644
--- a/ui/views/examples/single_split_view_example.cc
+++ b/ui/views/examples/single_split_view_example.cc
@@ -16,15 +16,15 @@ namespace {
 class SplittedView : public View {
  public:
   SplittedView();
-  virtual ~SplittedView();
+  ~SplittedView() override;
 
   void SetColor(SkColor from, SkColor to);
 
  private:
   // View:
-  virtual gfx::Size GetPreferredSize() const override;
-  virtual gfx::Size GetMinimumSize() const override;
-  virtual void Layout() override;
+  gfx::Size GetPreferredSize() const override;
+  gfx::Size GetMinimumSize() const override;
+  void Layout() override;
 
   DISALLOW_COPY_AND_ASSIGN(SplittedView);
 };