Integrate Chameleon capturing into video tests.

Video tests have been using native linux 'import' command to capture
screenshots. We are now using chameleon to capture the screenshots.
This serves as a first step to integrate chameleon into our video test
suite. We will do so only with peach_pit and roll out to other devices.

With this change we are also putting the logic to find chameleon ports
into a seperate class that can then be reused.

BUG=chromium:418217
TEST=Ran test on peach_pi.

Change-Id: I38b9ea3311b53eda937f9eb685c0dd24a24af059
Reviewed-on: https://chromium-review.googlesource.com/220202
Reviewed-by: Hung-ying Tyan <[email protected]>
Tested-by: Mussa Kiroga <[email protected]>
Commit-Queue: Mussa Kiroga <[email protected]>
11 files changed