Add mojo pipe for gamepad haptics commands

A new mojo pipe is added from blink::GamepadDispatcher to
device::GamepadHapticsManager to communicate haptics commands (play
effect, reset vibration).

BUG=749295

Change-Id: I20400aaca30165133a4b892e900f171e3bd48eda
Reviewed-on: https://chromium-review.googlesource.com/723848
Commit-Queue: Matt Reynolds <mattreynolds@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512658}
13 files changed