Mojo: Convert OVERRIDE -> override in various subdirectories of mojo/.

mojo/shell/dbus_application_loader_linux.h

Index: mojo/shell/dbus_application_loader_linux.h
diff --git a/mojo/shell/dbus_application_loader_linux.h b/mojo/shell/dbus_application_loader_linux.h
index c1cba4126e8203c35d645e707e1f82529e945766..ec0111fe6dc5b7ae37e7d3c8dc0a318b55e54d15 100644
--- a/mojo/shell/dbus_application_loader_linux.h
+++ b/mojo/shell/dbus_application_loader_linux.h
@@ -62,10 +62,10 @@ class DBusApplicationLoader : public ApplicationLoader {
   // "/org/chromium/MojoImpl".
   virtual void Load(ApplicationManager* manager,
                     const GURL& url,
-                    scoped_refptr<LoadCallbacks> callbacks) OVERRIDE;
+                    scoped_refptr<LoadCallbacks> callbacks) override;
 
   virtual void OnApplicationError(ApplicationManager* manager,
-                                  const GURL& url) OVERRIDE;
+                                  const GURL& url) override;
 
  private:
   class LoadContext;