tree 2a56c387326cb47da64ae0be0208ff7f52577e8a
parent 5bccbcf4c786a5f807abaf02e17faec4174141db
author Tom Wai-Hong Tam <waihong@chromium.org> 1464824306 +0800
committer chrome-bot <chrome-bot@chromium.org> 1465002216 -0700

Chameleon: Support an usage of only testing the first connected video port

This change adds a new usage of only testing the first connected video
port and ensuring it being plugged.

It is used via a with statement, like the following:
    finder = ChameleonVideoInputFinder(chameleon_board, display_facade)
    with finder.use_first_port() as chameleon_port:
        # chameleon_port is automatically plugged before this line.
        do_some_test_on(chameleon_port)
        # chameleon_port is automatically unplugged after this line.

BUG=b:28885370
TEST=Pending

Change-Id: I657a4f9d9d204535b2c7690177101064205e243a
Reviewed-on: https://chromium-review.googlesource.com/348871
Commit-Ready: Tom Tam <waihong@google.com>
Tested-by: Tom Tam <waihong@google.com>
Reviewed-by: Tom Tam <waihong@google.com>