add --descriptions flag to render_pictures tool

add --descriptions flag to render_pictures tool

Needed because right now, when you look at the full set of SKP results in
rebaseline_server, you can't tell which renderMode (or builder) generated each
one.

BUG=skia:2833
Committed: https://skia.googlesource.com/skia/+/b492c6ff308013eab3398992c10948997e348c45

[epoger, 2014-08-14 06:18:01]

Eric (and Stephan), PTAL at patchset 1.

https://codereview.chromium.org/466153006/diff/1/tools/render_pictures_main.cpp
File tools/render_pictures_main.cpp (right):

https://codereview.chromium.org/466153006/diff/1/tools/render_pictures_main.c...
tools/render_pictures_main.cpp:29: DEFINE_bool(bench_record, false, "If true,
drop into an infinite loop of recording the picture.");
reordered these to be alphabetical

[borenet, 2014-08-14 12:06:43]

Code LGTM, but I wonder whether it'd be better to have the buildbot scripts do
any desired manipulation of the JSON data after it's produced by
render_pictures.  Since this data isn't actually being used by the test, it
doesn't make sense to me that the test needs to see it at all.  I guess the
downside is that another piece of code would have to understand the layout of
the JSON data.

[epoger, 2014-08-14 14:22:29]

On 2014/08/14 12:06:43, borenet wrote:
> Code LGTM, but I wonder whether it'd be better to have the buildbot scripts do
> any desired manipulation of the JSON data after it's produced by
> render_pictures.  Since this data isn't actually being used by the test, it
> doesn't make sense to me that the test needs to see it at all.  I guess the
> downside is that another piece of code would have to understand the layout of
> the JSON data.

Yeah, I initially was thinking of making our Python buildbot code modify the
JSON after it was produced by render_pictures, but that would be another piece
of code that has to understand the JSON format.

I am not against moving in that direction later on, if a preponderance of the
evidence points in that direction. :-)

[epoger, 2014-08-14 14:22:35]

The CQ bit was checked by epoger@google.com

[commit-bot: I haz the power, 2014-08-14 14:23:30]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/epoger@google.com/466153006/1

[commit-bot: I haz the power, 2014-08-14 14:32:55]

Committed patchset #1 (1) as b492c6ff308013eab3398992c10948997e348c45