Revert of Remove PagePopup runtime flag (status=stable) for chromium (patchset #2 id:20001 of https://codereview.chromium.org/586053003/)

Reason for revert:
Broke <input type=color> UI on Android.

Original issue's description:
> Remove PagePopup runtime flag (status=stable) for chromium
>
> BUG=402536
>
> Committed: https://crrev.com/a0a8313cd7d7ae41ebd07c5fcba0c8659613fb87
> Cr-Commit-Position: refs/heads/master@{#298665}

TBR=avi@chromium.org,heeyoun.lee@samsung.com
NOTREECHECKS=true
NOTRY=true
BUG=402536

Review URL: https://codereview.chromium.org/641563002

Cr-Commit-Position: refs/heads/master@{#298669}
1 file changed