GitLab

Does the following minor refactoring, prompted by the fact that ANGLE
is in the process of adopting Gold and can make use of some existing
code if it's moved into the common implementation.

1. Moves //content/test/gpu/gpu_tests/skia_gold/gpu_skia_gold_session.py
   and its associated tests to
   //build/skia_gold_common/output_managerless_skia_gold_session.py.
2. Makes 'chrome' the default instance in SkiaGoldSessionManager since
   the GPU tests have moved to using that instance and thus all tests
   use the 'chrome' instance.
3. Makes _GetSessionClass() no longer protected and uses its return
   value in test runners instead of manually importing the class.

Bug: angleproject:4090
Change-Id: I1c2743d2dbe10e168f00e5f169f25fe9568c7c94
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2427354
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810055}