Bug 1243431 - [3.6] Add strings for Vibration API permission request doorhanger. r=margaret

mobile/android/locales/en-US/chrome/browser.properties

@@ -444,3 +444,8 @@ feedHandler.subscribeWith=Subscribe with
 # %1$S=name of the api that's deprecated, %2$S=New API to use. This may be a url to
 # a file they should import or the name of an api.
 nativeWindow.deprecated=%1$S is deprecated. Please use %2$S instead
+
+# Vibration API permission prompt
+vibrationRequest.message = Allow this site to vibrate your device?
+vibrationRequest.denyButton = Don't allow
+vibrationRequest.allowButton = Allow