GitLab

[ios] Adds collapse and context menu functionality to Recent Tabs Headers

- Adds expand/collapse functionality.
- Adds contextmenu functionality (Open All and Hide For now).
- Adds a tapGesture recognizer for headers.

Video:
https://drive.google.com/open?id=1LwJCMrUlNmJ73O_SWHEpImBqaEh4M1hv

Bug: 819462
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Idc51238b5cfb205f3150d33364efad83868c7333
Reviewed-on: https://chromium-review.googlesource.com/958099
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543535}