GitLab

Also:
* Refactor SharingBrowserTest to be explicit that there are
  always two sync clients, and set features for both "devices"
  so that default values don't matter
* Clean up context menu helper method

Bug: 1006264,989875
Change-Id: Ifc845eae13cef1c54bf982f5df7c9a3ea8f5f63b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1866512
Commit-Queue: Michael van Ouwerkerk <mvanouwerkerk@chromium.org>
Reviewed-by: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707316}