[Android] Reland CommandLine reset listeners.

This is a reland of https://codereview.chromium.org/1254973003, which I
had reverted in https://codereview.chromium.org/1263433002 because I
thought all calls to FeatureUtilities.isDocumentMode would now happen
after CommandLineFlags.setUp was called. This was mistaken and has
broken L bots.

BUG=516421
TBR=yfriedman@chromium.org,dgn@chromium.org

Review URL: https://codereview.chromium.org/1269083005

Cr-Commit-Position: refs/heads/master@{#341639}