Add mojom module suffix in .mojom files in content.

content/common/permission_service.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module content;
+module content.mojom;
 
 import "content/public/common/permission_status.mojom";
 
 enum PermissionName {
   GEOLOCATION,
   NOTIFICATIONS,
   PUSH_NOTIFICATIONS,
   MIDI,
   MIDI_SYSEX,
   PROTECTED_MEDIA_IDENTIFIER,
@@ skipping 17 matching lines @@
 
   // Runs the callback next time there is a permission status change for the
   // given { permission, origin }. Callers of this method will have to call it
   // again if they want to keep listening to the changes. To prevent race
   // conditions, the caller must pass the last known value.
   GetNextPermissionChange(PermissionName permission,
                           string origin,
                           PermissionStatus last_known_status)
     => (PermissionStatus status);
 };