GitLab

The version of GTK3 used in Debian stretch does not use clipboard data
marked as test/plain, but will use UTF8_STRING.

Bug: 793688
Test: Paste from Chrome into gedit
Change-Id: Id1b08e270fd385d287c729fe5594832753b845df
Reviewed-on: https://chromium-review.googlesource.com/1000523
Commit-Queue: Zach Reizner <zachr@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549074}