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

chrome/browser/extensions/api/file_system/file_system_apitest.cc

Index: chrome/browser/extensions/api/file_system/file_system_apitest.cc
diff --git a/chrome/browser/extensions/api/file_system/file_system_apitest.cc b/chrome/browser/extensions/api/file_system/file_system_apitest.cc
index 91939f7c068af7accb134cbdac0b23a3e91e08b0..4b1861df539fa9f1e63a6c0e9e69551f12f9db4a 100644
--- a/chrome/browser/extensions/api/file_system/file_system_apitest.cc
+++ b/chrome/browser/extensions/api/file_system/file_system_apitest.cc
@@ -31,8 +31,8 @@ class AppLoadObserver : public ExtensionRegistryObserver {
     extension_registry_observer_.Add(ExtensionRegistry::Get(browser_context));
   }
 
-  virtual void OnExtensionLoaded(content::BrowserContext* browser_context,
-                                 const Extension* extension) override {
+  void OnExtensionLoaded(content::BrowserContext* browser_context,
+                         const Extension* extension) override {
     callback_.Run(extension);
   }
 
@@ -64,7 +64,7 @@ const int kGraylistedPath = base::DIR_HOME;
 
 class FileSystemApiTest : public PlatformAppBrowserTest {
  public:
-  virtual void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(CommandLine* command_line) override {
     PlatformAppBrowserTest::SetUpCommandLine(command_line);
     test_root_folder_ = test_data_dir_.AppendASCII("api_test")
         .AppendASCII("file_system");
@@ -72,9 +72,7 @@ class FileSystemApiTest : public PlatformAppBrowserTest {
         "test_root", test_root_folder_);
   }
 
-  virtual void SetUpOnMainThread() override {
-    ClearCommandLineArgs();
-  }
+  void SetUpOnMainThread() override { ClearCommandLineArgs(); }
 
   virtual void TearDown() override {
     FileSystemChooseEntryFunction::StopSkippingPickerForTest();