Clamp values for playbackRate in HTMLMediaElement.

Previous change removed clamping for non-experimental case.

Bug: 775504, 775504, 775829, 775501, 747082
Change-Id: I90eec1b3e99b2370ccd05669c3160399ca235bbc
Reviewed-on: https://chromium-review.googlesource.com/727119
Commit-Queue: apacible <apacible@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510318}
2 files changed