Standardize usage of virtual/override/final in chrome/browser/extensions/

chrome/browser/extensions/bookmark_app_helper.cc

Index: chrome/browser/extensions/bookmark_app_helper.cc
diff --git a/chrome/browser/extensions/bookmark_app_helper.cc b/chrome/browser/extensions/bookmark_app_helper.cc
index cc1c384e6e25a22afea8eccb312d0713814211a2..b92920c688ff87d05e0dc4294f8087bc1911a7cc 100644
--- a/chrome/browser/extensions/bookmark_app_helper.cc
+++ b/chrome/browser/extensions/bookmark_app_helper.cc
@@ -48,11 +48,11 @@ class GeneratedIconImageSource : public gfx::CanvasImageSource {
         letter_(letter),
         color_(color),
         output_size_(output_size) {}
-  virtual ~GeneratedIconImageSource() {}
+  ~GeneratedIconImageSource() override {}
 
  private:
   // gfx::CanvasImageSource overrides:
-  virtual void Draw(gfx::Canvas* canvas) override {
+  void Draw(gfx::Canvas* canvas) override {
     const unsigned char kLuminanceThreshold = 190;
     const int icon_size = output_size_ * 3 / 4;
     const int icon_inset = output_size_ / 8;