CC Animation: Fix impl SetNeedsCommit. Port LayerTreeHostImplTests to use animation timelines.

Also includes the fix: We don't want to request a commit from impl side if we add animation to impl-side animation players.

We preserve the old version of tests so we can fall back at any time.

BUG=394777
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CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1558943002

Cr-Commit-Position: refs/heads/master@{#367719}
4 files changed