dm/gold: Let's consider source_type a key.

dm/gold: Let's consider source_type a key.

Ex.

   "results" : [
      {
         "key" : {
            "config" : "565",
            "mode" : "direct",
            "name" : "textblob",
            "source_type" : "GM"
         },
         "md5" : "024ecfc3be8c08ea0cc580c12411fe09"
      },

BUG=skia:3255
Committed: https://skia.googlesource.com/skia/+/3d8878caa74c58f95e0f4cb5ebd40c8771567c13

[mtklein, 2014-12-18 19:49:04]

mtklein@google.com changed reviewers:
+ mtklein@google.com, stephana@google.com

[mtklein, 2014-12-18 19:49:58]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-12-18 19:50:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/811403003/1

[commit-bot: I haz the power, 2014-12-18 19:50:23]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2014-12-19 01:50 UTC

[commit-bot: I haz the power, 2014-12-19 02:07:23]

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

[commit-bot: I haz the power, 2014-12-19 02:07:24]

No LGTM from a valid reviewer yet. Please ask for an LGTM from a
full Skia committer from
https://skia.googlesource.com/skia/+/master/CQ_COMMITTERS

[stephana, 2014-12-19 04:07:45]

On 2014/12/19 02:07:24, I haz the power (commit-bot) wrote:
> No LGTM from a valid reviewer yet. Please ask for an LGTM from a
> full Skia committer from
> https://skia.googlesource.com/skia/+/master/CQ_COMMITTERS

LGTM

[mtklein, 2015-01-05 14:23:06]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-05 14:24:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/811403003/1

[commit-bot: I haz the power, 2015-01-05 14:47:43]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/3d8878caa74c58f95e0f4cb5ebd40c8771567c13