[Merge] lp:~canonical-platform-qa/webbrowser-app/autopkgtest into lp:webbrowser-app

[Vincent Ladeuil]

This now passes the tests against the current archive, -proposed and the phone (krillin devel-proposed 196).

@Leo: Feedback welcome, there may still be some rough edges and bits we'd like to be ready for reuse in other projects but I think that can wait.
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https://code.launchpad.net/~canonical-platform-qa/webbrowser-app/autopkgtest/+merge/256858
Your team Ubuntu Phablet Team is requested to review the proposed merge of lp:~canonical-platform-qa/webbrowser-app/autopkgtest into lp:webbrowser-app.