[SendTabToSelf][ios] add the ability to pick the target device.

This uses the new showActivityServiceContextMenu to display an action
sheet with the target devices for sending tabs.

Bug: 949226
Change-Id: Ifa01d85f901d0a64dbae71114febe9224c75db62
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1610992
Reviewed-by: Peter Lee <pkl@chromium.org>
Reviewed-by: sebsg <sebsg@chromium.org>
Auto-Submit: Jeffrey Cohen <jeffreycohen@chromium.org>
Commit-Queue: Jeffrey Cohen <jeffreycohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663289}
9 files changed