Retire FeaturePolicyForPermissions flag

Feature Policy support for EME shipped in M64
https://chromium-review.googlesource.com/696944

BUG=689802

Change-Id: I03a3f706a4492bbb2e4112dce66d68281fe172b3
Reviewed-on: https://chromium-review.googlesource.com/1166619
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581528}
5 files changed