Add power test to video_PlaybackPerf

Add power test to video_PlaybackPerf and remove
video_PlaybackPower. Thus we can reuse the function
in video_PlaybackPerf for power test.

BUG=chromium:391396
TEST=test on peach_pit
CQ-DEPEND=CL:213992

Change-Id: I8ba966b95a186fd1bfb8b554f433d24a7d215063
Reviewed-on: https://chromium-review.googlesource.com/213782
Reviewed-by: Wu-Cheng Li <wuchengli@chromium.org>
Commit-Queue: Wen-Ding Li <wending@google.com>
Tested-by: Wen-Ding Li <wending@google.com>
10 files changed