make CT skia_try_server work with updated render_pictures JSON

make CT skia_try_server work with updated render_pictures JSON

needed to stay in sync with https://codereview.chromium.org/226293002

BUG=skia:2230
NOTREECHECKS=True
NOTRY=True

Committed: https://skia.googlesource.com/buildbot/+/9f8d1f8fe5387a78a145e4626193f081c5e89529

[epoger, 2014-04-07 22:08:00]

PTAL

https://codereview.chromium.org/227673005/diff/1/compute_engine_scripts/telem...
File
compute_engine_scripts/telemetry/telemetry_slave_scripts/write_json_summary.py
(right):

https://codereview.chromium.org/227673005/diff/1/compute_engine_scripts/telem...
compute_engine_scripts/telemetry/telemetry_slave_scripts/write_json_summary.py:155:
return re.sub('-tile\d+$', '', skp_file_and_tile)
This still relies on a "magic" conversion algorithm!  I think this means that we
should re-evaluate the new JSON format we settled on in
https://codereview.chromium.org/226293002 , and make it explicit about which SKP
each tile image came from.

Let's discuss live on Tuesday...

[epoger, 2014-04-09 20:33:04]

Ravi- Please review at patchset 4.

The unittests and implementation are now up-to-date with the latest patchset (5)
in https://codereview.chromium.org/226293002/ ('add explicit filepaths to
render_pictures JSON summary')

[rmistry, 2014-04-10 11:47:58]

LGTM

[epoger, 2014-04-10 15:37:11]

The CQ bit was checked by epoger@google.com

[commit-bot: I haz the power, 2014-04-10 15:37:13]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/epoger@google.com/227673005/70001

[commit-bot: I haz the power, 2014-04-10 15:37:20]

Change committed as 9f8d1f8fe5387a78a145e4626193f081c5e89529