GitLab

Update logic for counting spare compositors (otherwise would be broken
by this change), and add optional "force new compositor" argument.

This is a speculative "revert", to determine the cause for GPU crashes
in GLFence::Create.

Bug: 863817
Change-Id: I47cae1fb78e73481d1272d4ce9d56b19dcb4079c
Reviewed-on: https://chromium-review.googlesource.com/1138872Reviewed-by: ccameron <ccameron@chromium.org>
Reviewed-by: Leonard Grey <lgrey@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575441}