DM: add --writePath

DM: add --writePath

For fun, make the output prettier, hiding ", N failures" unless there is one.

BUG=
R=bsalomon@google.com

Committed: https://code.google.com/p/skia/source/detail?r=11867

[mtklein, 2013-10-18 16:12:38]

I know you guys use this feature of GM a lot, so I figured you'd like a look.

[bsalomon, 2013-10-18 16:31:42]

On 2013/10/18 16:12:38, mtklein wrote:
> I know you guys use this feature of GM a lot, so I figured you'd like a look.

Where do the filenames come from?

In GM we write <test_name>_<config>.png unless the --hierarchy flag is passed.
Then it is <config>/<test_name>.png. Can we make this latter version the default
or only supported mode for DM? I think it is more useful (mostly for diffing
configs against each other) and that the current default only exists for
historical reasons.

[mtklein, 2013-10-18 20:10:04]

On 2013/10/18 16:31:42, bsalomon wrote:
> On 2013/10/18 16:12:38, mtklein wrote:
> > I know you guys use this feature of GM a lot, so I figured you'd like a
look.
> 
> Where do the filenames come from?
> 
> In GM we write <test_name>_<config>.png unless the --hierarchy flag is passed.
> Then it is <config>/<test_name>.png. Can we make this latter version the
default
> or only supported mode for DM? I think it is more useful (mostly for diffing
> configs against each other) and that the current default only exists for
> historical reasons.

Done!  It's the default and only version now.  PTAL

[bsalomon, 2013-10-18 20:32:41]

lgtm

[commit-bot: I haz the power, 2013-10-18 20:35:07]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/mtklein@google.com/29293003/110001

[mtklein, 2013-10-18 20:52:49]

Committed patchset #4 manually as r11867 (presubmit successful).