GitLab

Fixes up various dependency bugs that prevent mojo_demo_launcher +
mojo_html_viewer from working.

Once we are gn check clean this should be easy to enforce with a script,
but for now it's manual testing.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/608023002

Cr-Commit-Position: refs/heads/master@{#297023}