UI Compositor: Fix unit tests to work if no use_compositor_animation_timelines
UI Compositor: Fix unit tests to work if no use_compositor_animation_timelines

BUG=574859

Review URL: https://codereview.chromium.org/1659283003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#373300}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk