Standardize usage of virtual/override/final in mojo/

mojo/shell/dynamic_application_loader.cc

Index: mojo/shell/dynamic_application_loader.cc
diff --git a/mojo/shell/dynamic_application_loader.cc b/mojo/shell/dynamic_application_loader.cc
index eae422d10f274ffae735460f3d04b3017baaf868..1627aa99a00c8f2405b6f030564fa3fad070cf69 100644
--- a/mojo/shell/dynamic_application_loader.cc
+++ b/mojo/shell/dynamic_application_loader.cc
@@ -115,7 +115,7 @@ class DynamicApplicationLoader::LocalLoader : public Loader {
                    base::PathExists(path)));
   }
 
-  virtual ~LocalLoader() {}
+  ~LocalLoader() override {}
 
  private:
   base::WeakPtrFactory<LocalLoader> weak_ptr_factory_;
@@ -152,7 +152,7 @@ class DynamicApplicationLoader::NetworkLoader : public Loader {
                                   weak_ptr_factory_.GetWeakPtr()));
   }
 
-  virtual ~NetworkLoader() {
+  ~NetworkLoader() override {
     if (!file_.empty())
       base::DeleteFile(file_, false);
   }