GitLab

* Remove unnecessary top_right() calls
* Use temps to reduce wrapping
* Use WindowFromTarget() more consistently
* For parallelism, always convert from targets to windows, instead of sometimes
  using the "target" version and sometimes the "window" version and mixing calls
* Group all the EventGenerator constructor variants that take a root window

Bug: none
Change-Id: I707780ee21ec2d3652fd3d1a38e3607e1ba980be
Reviewed-on: https://chromium-review.googlesource.com/c/1347277
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611291}