OnionSoup: Move notification_service.mojom to public/mojom/notifications

This CL moves notification_service.mojom from
public/platform/modules/notifications to public/mojom/notifications
to gather mojom files to mojom folder and updates paths for
notification_service.mojom.

Bug: 919393
Change-Id: I4db45211179791180990358dc97bceaad31b41ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1530490
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Commit-Queue: Julie Jeongeun Kim <jkim@igalia.com>
Cr-Commit-Position: refs/heads/master@{#643314}
14 files changed