Add webusb notification UI code

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 7e77808db3322ce6322bb83a70b872df4292412f..7eed493f57f4bc0745a08a4af53221d4d67ea0a5 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -5068,6 +5068,14 @@ Keep your key file in a safe place. You will need it to create new versions of y
         Keep changes
       </message>
 
+      <!-- WebUsb Notifications Flag -->
+      <message name="IDS_FLAGS_ENABLE_WEBUSB_NOTIFICATIONS_NAME" desc="Title for the flag which enables WebUsb notifications.">
+        WebUsb notifications.
+      </message>
+      <message name="IDS_FLAGS_ENABLE_WEBUSB_NOTIFICATIONS_DESCRIPTION" desc="Description for the flag which enables WebUsb notifications.">
+        Experimental WebUsb notifications.
+      </message>
+
       <!-- chrome://settings-frame/options_settings_app.html for the App Launcher Settings App -->
       <if expr="enable_settings_app">
         <message name="IDS_SETTINGS_APP_LAUNCHER_PRODUCT_NAME" desc="Product name to use when referring to applications running in the App Launcher inside the non-browser Settings App">