GitLab

We should wait for Runtime.addBinding to finish
before proceeding with the test.

Bug: none
Change-Id: I06be299d5f74c69818b92c09eaea6c422ac0bed2
Reviewed-on: https://chromium-review.googlesource.com/c/1483361Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634782}