Support for connecting to localhost on the chromoting test driver.

Completed connection to localhost. I've added a new StartConnection method in TestChromotingClient which reuses almost all of the code provided to create a chromoting connection. In addition, I've added a new parameter called "client-pin", which will allow for the user to pass in a PIN to authenticate the connection.

BUG=

Review URL: https://codereview.chromium.org/1237093004

Cr-Commit-Position: refs/heads/master@{#339504}
13 files changed