This is a reland of 6252427ab5415839618a0d25e4f6e61becce3923.
Original change's description:
> Add WPT tests for feature policy
>
> 1. Added tests for header policy.
> a. document.policy shows correctly parsed policy
> b. local / remote iframes without allow attribute correctly inherit
> document.policy
> c. dynamically update allow attribute updates the policy correctly.
>
> 2. Added tests for nested policies.
>
> Bug: 732003
> Change-Id: I869449f6bba89fc58997355df27249f403d76808
> Reviewed-on: https://chromium-review.googlesource.com/796952
> Commit-Queue: Luna Lu <[email protected]>
> Reviewed-by: Ian Clelland <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#531698}
Bug: 732003
Change-Id: I46065efff8c5af2d5279721f3c759580b0807e05
Reviewed-on: https://chromium-review.googlesource.com/887324
Reviewed-by: Ian Clelland <[email protected]>
Commit-Queue: Luna Lu <[email protected]>
Cr-Commit-Position: refs/heads/master@{#538904}