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

chrome/browser/prefetch/prefetch_browsertest.cc

Index: chrome/browser/prefetch/prefetch_browsertest.cc
diff --git a/chrome/browser/prefetch/prefetch_browsertest.cc b/chrome/browser/prefetch/prefetch_browsertest.cc
index ffe6ca6d8b54da71a82dcdc5c44f8d630025a89a..cd3b57e796b94a2271d695057cc66b5fb909d12d 100644
--- a/chrome/browser/prefetch/prefetch_browsertest.cc
+++ b/chrome/browser/prefetch/prefetch_browsertest.cc
@@ -32,14 +32,14 @@ const char kPrefetchPage[] = "files/prerender/simple_prefetch.html";
 
 class MockNetworkChangeNotifierWIFI : public NetworkChangeNotifier {
  public:
-  virtual ConnectionType GetCurrentConnectionType() const override {
+  ConnectionType GetCurrentConnectionType() const override {
     return NetworkChangeNotifier::CONNECTION_WIFI;
   }
 };
 
 class MockNetworkChangeNotifier4G : public NetworkChangeNotifier {
  public:
-  virtual ConnectionType GetCurrentConnectionType() const override {
+  ConnectionType GetCurrentConnectionType() const override {
     return NetworkChangeNotifier::CONNECTION_4G;
   }
 };
@@ -49,7 +49,7 @@ class PrefetchBrowserTestBase : public InProcessBrowserTest {
   explicit PrefetchBrowserTestBase(bool disabled_via_field_trial)
       : disabled_via_field_trial_(disabled_via_field_trial) {}
 
-  virtual void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(CommandLine* command_line) override {
     if (disabled_via_field_trial_) {
       command_line->AppendSwitchASCII(switches::kForceFieldTrials,
                                       "Prefetch/ExperimentDisabled/");
@@ -95,10 +95,10 @@ class HangingURLRequestJob : public net::URLRequestJob {
       : net::URLRequestJob(request, network_delegate) {}
 
   // net::URLRequestJob implementation
-  virtual void Start() override {}
+  void Start() override {}
 
  private:
-  virtual ~HangingURLRequestJob() {}
+  ~HangingURLRequestJob() override {}
 
   DISALLOW_COPY_AND_ASSIGN(HangingURLRequestJob);
 };
@@ -108,9 +108,9 @@ class HangingRequestInterceptor : public net::URLRequestInterceptor {
   explicit HangingRequestInterceptor(const base::Closure& callback)
       : callback_(callback) {}
 
-  virtual ~HangingRequestInterceptor() {}
+  ~HangingRequestInterceptor() override {}
 
-  virtual net::URLRequestJob* MaybeInterceptRequest(
+  net::URLRequestJob* MaybeInterceptRequest(
       net::URLRequest* request,
       net::NetworkDelegate* network_delegate) const override {
     if (!callback_.is_null())