Remove unnecessary 'virtual' annotation from mojo

mojo/services/html_viewer/webstoragenamespace_impl.h

Index: mojo/services/html_viewer/webstoragenamespace_impl.h
diff --git a/mojo/services/html_viewer/webstoragenamespace_impl.h b/mojo/services/html_viewer/webstoragenamespace_impl.h
index 32e17c051da1ce36c46716c1508c978bf4455754..042f982f99791990f170f3a043e91b22cc9892a4 100644
--- a/mojo/services/html_viewer/webstoragenamespace_impl.h
+++ b/mojo/services/html_viewer/webstoragenamespace_impl.h
@@ -15,12 +15,12 @@ class WebStorageNamespaceImpl : public blink::WebStorageNamespace {
   WebStorageNamespaceImpl();
 
  private:
-  virtual ~WebStorageNamespaceImpl();
+  ~WebStorageNamespaceImpl() override;
 
   // blink::WebStorageNamespace methods:
-  virtual blink::WebStorageArea* createStorageArea(
-      const blink::WebString& origin);
-  virtual bool isSameNamespace(const blink::WebStorageNamespace&) const;
+  blink::WebStorageArea* createStorageArea(
+      const blink::WebString& origin) override;
+  bool isSameNamespace(const blink::WebStorageNamespace&) const override;
 
   DISALLOW_COPY_AND_ASSIGN(WebStorageNamespaceImpl);
 };