GitLab

- Make visibility test logic consistent across multiple methods.
- Document a broken 'only this set of visible elements' method.
- Make visibility testing ignore transience, to avoid having to advance
  time to test final values.
- Move the render-order test in with the other UI tests, and simplify.
- Always run the bingings after a scene is constructed, to set state.
- Remove the bulk of needless time-advances for visibility testing.

BUG=

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I8b357131083cc18847bdce3c94210c926b113748
Reviewed-on: https://chromium-review.googlesource.com/788282Reviewed-by: Ian Vollick <vollick@chromium.org>
Reviewed-by: Biao She <bshe@chromium.org>
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519103}