GitLab

Mostly cosmetic API changes. The guts of TimeDeltaInterpolator were
spruced up a bit.

BUG=370634

Review URL: https://codereview.chromium.org/376013003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282186 0039d316-1c4b-4281-b951-d872f2087c98