Standardize usage of virtual/override/final in extensions/

extensions/browser/extension_error.h

Index: extensions/browser/extension_error.h
diff --git a/extensions/browser/extension_error.h b/extensions/browser/extension_error.h
index 0fc0ee55b951ea68c9e4a57bb2ac4ce0ec2c3111..ba44d554862518e620e6daffedb1f41706c85f3c 100644
--- a/extensions/browser/extension_error.h
+++ b/extensions/browser/extension_error.h
@@ -94,11 +94,11 @@ class ManifestError : public ExtensionError {
                 const base::string16& message,
                 const base::string16& manifest_key,
                 const base::string16& manifest_specific);
-  virtual ~ManifestError();
+  ~ManifestError() override;
 
-  virtual scoped_ptr<base::DictionaryValue> ToValue() const override;
+  scoped_ptr<base::DictionaryValue> ToValue() const override;
 
-  virtual std::string PrintForTest() const override;
+  std::string PrintForTest() const override;
 
   const base::string16& manifest_key() const { return manifest_key_; }
   const base::string16& manifest_specific() const { return manifest_specific_; }
@@ -108,7 +108,7 @@ class ManifestError : public ExtensionError {
   static const char kManifestSpecificKey[];
 
  private:
-  virtual bool IsEqualImpl(const ExtensionError* rhs) const override;
+  bool IsEqualImpl(const ExtensionError* rhs) const override;
 
   // If present, this indicates the feature in the manifest which caused the
   // error.
@@ -131,11 +131,11 @@ class RuntimeError : public ExtensionError {
                logging::LogSeverity level,
                int render_view_id,
                int render_process_id);
-  virtual ~RuntimeError();
+  ~RuntimeError() override;
 
-  virtual scoped_ptr<base::DictionaryValue> ToValue() const override;
+  scoped_ptr<base::DictionaryValue> ToValue() const override;
 
-  virtual std::string PrintForTest() const override;
+  std::string PrintForTest() const override;
 
   const GURL& context_url() const { return context_url_; }
   const StackTrace& stack_trace() const { return stack_trace_; }
@@ -153,7 +153,7 @@ class RuntimeError : public ExtensionError {
   static const char kRenderViewIdKey[];
 
  private:
-  virtual bool IsEqualImpl(const ExtensionError* rhs) const override;
+  bool IsEqualImpl(const ExtensionError* rhs) const override;
 
   // Since we piggy-back onto other error reporting systems (like V8 and
   // WebKit), the reported information may need to be cleaned up in order to be