Fix for google:instantExtendedEnabledKey replacement

This is fix for minor bug that was inserted in
google:instantExtendedEnabledKey replacement in
https://codereview.chromium.org/2516963002/.
Incorrect string literal was used in replacement.

R=treib@chromium.org, pkasting@chromium.org

Review-Url: https://codereview.chromium.org/2524733008
Cr-Commit-Position: refs/heads/master@{#434456}
2 files changed