Add module suffix in .mojom files for components/arc

components/arc/common/input.mojom

 // Copyright 2015 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 arc;
+module arc.mojom;
 
 interface InputInstance {
   // Registers a virtual input device on the container side.
   // |name| is the device name, like "Chrome OS Keyboard".
   // |device_type| is the device type, like "keyboard".
   // The virtual device will be reading 'struct input_event's from |fd|.  The
   // ownership of |fd| will be transferred to the receiver, so the sender must
   // not close it.
   RegisterInputDevice(string name,
                       string device_type,
                       handle fd);
 };