Chameleon: Refactor methods of getting display name, resolution, and screenshot

* Move the major logic to the client
* Make the method names more consistent
* Use False instead of None when no display found, same as the graphic library

BUG=chromium:405143
TEST=Ran affected tests, like display_EdidStress, passed

Change-Id: I5df1bb8294152d263d1e2c2ff6460953c0884791
Reviewed-on: https://chromium-review.googlesource.com/226108
Reviewed-by: Wai-Hong Tam <waihong@chromium.org>
Commit-Queue: Wai-Hong Tam <waihong@chromium.org>
Tested-by: Wai-Hong Tam <waihong@chromium.org>
7 files changed