Add scrolling screenshare test to full_stack perf tests.

Add scrolling screenshare test to full_stack perf tests.

BUG=
R=pbos@webrtc.org

Committed: https://chromium.googlesource.com/external/webrtc/+/6ee69aa94c8d3d84d6b30462e38004a465af0a7e

[sprang_webrtc, 2015-08-20 15:36:46]

sprang@webrtc.org changed reviewers:
+ mflodman@webrtc.org

[sprang_webrtc, 2015-08-31 13:17:21]

sprang@webrtc.org changed reviewers:
+ pbos@webrtc.org
- mflodman@webrtc.org

[sprang_webrtc, 2015-08-31 13:17:22]

Reassigning to pbos

[pbos-webrtc, 2015-09-03 09:38:24]

lgtm

[sprang_webrtc, 2015-09-03 11:55:20]

The CQ bit was checked by sprang@webrtc.org

[commit-bot: I haz the power, 2015-09-03 11:55:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1298613004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1298613004/1

[commit-bot: I haz the power, 2015-09-03 13:55:40]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-03 13:55:41]

Try jobs failed on following builders:
  android on tryserver.webrtc (JOB_TIMED_OUT, no build URL)
  android_rel on tryserver.webrtc (JOB_TIMED_OUT, no build URL)

[sprang_webrtc, 2015-09-03 13:58:23]

Committed patchset #1 (id:1) manually as
6ee69aa94c8d3d84d6b30462e38004a465af0a7e (presubmit successful).