Add a DHCECK guard to the usage of the cusco extension API.

Chrome is no longer supposed to call the chrome-cusco-api Google API. This
Cl ensures that the application crashes in debug mode if such an attempt is
made to validate this assumption.

Bug: 968923

Change-Id: Ie6fbc665ebc02ea078a7e4ea122da7111811a70a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1670874
Commit-Queue: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#674769}
1 file changed