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This makes the settings into proper GN args that can be overridden.
Also added "remoting" to their names since they are remoting-specific.
Also fixed the Cardboard-enabled build (code was expecting '1'/'0' but
GN was supplying 'true'/'false').

Review URL: https://codereview.chromium.org/1637093002

Cr-Commit-Position: refs/heads/master@{#371602}