cc: Prevent unit tests from using Now() as the impl frame time.
Unit tests using FakeLayerTreeHostImpl should not use Now() as the
frame time, as this is racey/problematic. For instance it may not change
fast enough to let your test produce 2 outputs at different Now() times.
Re-enable 2 tests that were failing because of this problem in the test
harness.
R=enne, jbedley
BUG=393733
Review URL: https://codereview.chromium.org/
444053004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288029 0039d316-1c4b-4281-b951-d872f2087c98