[mediacapture-streams-tests] Check disabled-video at next frame (#1173)

If test checks pixels of video element at same frame, video element has
privious frame not blackness, because video element wasn't rederred after track
was disabled.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1173

Received on Thursday, 14 August 2014 07:19:04 UTC