[Picture-in-Picture] Do not require feature flag for Web API.

This CL makes sure Picture-in-Picture Web API does not require
kPictureInPicture feature flag for Origin Trial.

Bug: 806249
Change-Id: I502e2337e9e9c1bc519aef61755a475f66d0f8cc
Reviewed-on: https://chromium-review.googlesource.com/1069009
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/heads/master@{#561067}
2 files changed