Standardize usage of virtual/override/final in extensions/

extensions/common/manifest_handlers/web_accessible_resources_info.h

Index: extensions/common/manifest_handlers/web_accessible_resources_info.h
diff --git a/extensions/common/manifest_handlers/web_accessible_resources_info.h b/extensions/common/manifest_handlers/web_accessible_resources_info.h
index eea1cd3307b2e6c209c6009abcc09a9d23b976f9..6e6143da4280520fea4f483e3fd7d739628c7c80 100644
--- a/extensions/common/manifest_handlers/web_accessible_resources_info.h
+++ b/extensions/common/manifest_handlers/web_accessible_resources_info.h
@@ -18,7 +18,7 @@ namespace extensions {
 struct WebAccessibleResourcesInfo : public Extension::ManifestData {
   // Define out of line constructor/destructor to please Clang.
   WebAccessibleResourcesInfo();
-  virtual ~WebAccessibleResourcesInfo();
+  ~WebAccessibleResourcesInfo() override;
 
   // Returns true if the specified resource is web accessible.
   static bool IsResourceWebAccessible(const Extension* extension,
@@ -35,12 +35,12 @@ struct WebAccessibleResourcesInfo : public Extension::ManifestData {
 class WebAccessibleResourcesHandler : public ManifestHandler {
  public:
   WebAccessibleResourcesHandler();
-  virtual ~WebAccessibleResourcesHandler();
+  ~WebAccessibleResourcesHandler() override;
 
-  virtual bool Parse(Extension* extension, base::string16* error) override;
+  bool Parse(Extension* extension, base::string16* error) override;
 
  private:
-  virtual const std::vector<std::string> Keys() const override;
+  const std::vector<std::string> Keys() const override;
 
   DISALLOW_COPY_AND_ASSIGN(WebAccessibleResourcesHandler);
 };