Re-land: Fix Website Settings crash with Plugins ASK setting.

This reverts commit 09eafe7304589043a9b9aa34b9ef559ead1e8e59.

TBR=tommycli@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/790123003

Cr-Commit-Position: refs/heads/master@{#309573}
3 files changed