Merge to M44: "Drop frames less than a millisecond apart in media time."

Merge to M44: "Drop frames less than a millisecond apart in media time."

Our rendering path has no reasonable expectation of being able to
render 1000fps content, so these are bad timestamps that end up
wrecking assumptions throughout the rendering pathway.

Instead of trying to guard against these frames everywhere, just
discard them immediately during enqueue.

BUG=488302
TEST=new unittest
TBR=xhwang

Review URL: https://codereview.chromium.org/1142723002

Cr-Commit-Position: refs/heads/master@{#330458}
(cherry picked from commit b5814778060deb32c31605bfe0b82cd2baeae866)

[DaleCurtis, 2015-05-21 01:30:42]

Committed patchset #1 (id:1) to pending queue manually as
cbd73b2480cd9c0162bca8ec8e0714a45921b2ae (presubmit successful).