Validate frame after conversion in chrome.send

BUG=797511
TEST=Manually, see https://crbug.com/797511#c1
TBR=rob@robwu.nl

(cherry picked from commit 90585e657db48f93bd73bc45d4caa975323da41b)

Change-Id: Ib1a99db4d7648fb1325eb6d7af4ef111d6dda4cb
Reviewed-on: https://chromium-review.googlesource.com/844076
Commit-Queue: Rob Wu <rob@robwu.nl>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#526197}
Reviewed-on: https://chromium-review.googlesource.com/874471
Reviewed-by: Rob Wu <rob@robwu.nl>
Cr-Commit-Position: refs/branch-heads/3282@{#541}
Cr-Branched-From: 5fdc0fab22ce7efd32532ee989b223fa12f8171e-refs/heads/master@{#520840}
1 file changed