[Android] Silence flag_changer on missing command-line file.
[Android] Silence flag_changer on missing command-line file.

BUG=542144

Review URL: https://codereview.chromium.org/1389223003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#354186}

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