Standardize usage of virtual/override/final specifiers.

extensions/browser/extension_icon_image_unittest.cc

Index: extensions/browser/extension_icon_image_unittest.cc
diff --git a/extensions/browser/extension_icon_image_unittest.cc b/extensions/browser/extension_icon_image_unittest.cc
index 4842083d958e8438f0a20c36b2a28e865777c2dd..9f89fc2c50aee9541f1c6f2c915f47f6e0c75a71 100644
--- a/extensions/browser/extension_icon_image_unittest.cc
+++ b/extensions/browser/extension_icon_image_unittest.cc
@@ -125,7 +125,7 @@ class ExtensionIconImageTest : public ExtensionsTest,
         io_thread_(BrowserThread::IO),
         notification_service_(content::NotificationService::Create()) {}
 
-  virtual ~ExtensionIconImageTest() {}
+  ~ExtensionIconImageTest() override {}
 
   void WaitForImageLoad() {
     quit_in_image_loaded_ = true;
@@ -167,7 +167,7 @@ class ExtensionIconImageTest : public ExtensionsTest,
   }
 
   // testing::Test overrides:
-  virtual void SetUp() override {
+  void SetUp() override {
     file_thread_.Start();
     io_thread_.Start();
   }