[ChromeDriver] Handle pauses in Perform Actions

W3C spec allows the app to specify pauses within Perform Actions command
(https://w3c.github.io/webdriver/#dfn-dispatch-actions). Updating
ChromeDriver to handle these pauses.

Bug: chromedriver:1897
Change-Id: I533179f4a9f2216bfacf0f4fdb539c8f898bed07
Reviewed-on: https://chromium-review.googlesource.com/c/1392281
Commit-Queue: John Chen <johnchen@chromium.org>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619506}
2 files changed