Add tests for InputDevice/TouchscreenDevice StructTraits.

ui/events/devices/mojo/device_traits_test_service.mojom

 // Copyright 2016 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 skia.mojom;
+module ui.mojom;
 
-import "skia/public/interfaces/bitmap.mojom";
-import "skia/public/interfaces/image_filter.mojom";
+import "ui/events/devices/mojo/input_devices.mojom";
 
 // All functions on this interface echo their arguments to test StructTraits
 // serialization and deserialization.
-interface TraitsTestService {
+interface DeviceTraitsTestService {

[Ken Rockot(use gerrit already), 2016/06/27 15:34:33]

DeviceTraitsTest is fine (no Service suffixes please)

[kylechar, 2016/06/27 15:44:25]

Done.

   [Sync]
-  EchoBitmap(Bitmap b) => (Bitmap pass);
+  EchoInputDevice(InputDevice in) => (InputDevice out);
 
   [Sync]
-  EchoImageFilter(ImageFilter i) => (ImageFilter pass);
+  EchoTouchscreenDevice(TouchscreenDevice in) => (TouchscreenDevice out);
 };