arc: Show custom notification via notification surface
- ArcCustomotificationItem to use notification surface to create Chrome
notification;
- ArcCustomNotificationView to host and show the notification surface;
- Add a use_custom_notification property to ArcNotificationData;
- ArcNotificationManager choose ArcNotificationItem
or ArcCustomNotificationItem based on that property;
BUG=b/25816173
Review-Url: https://codereview.chromium.org/2066853002
Cr-Commit-Position: refs/heads/master@{#401802}
15 files changed