Add description for WebFont.PackageFormat histogram

Add description for WebFont.PackageFormat histogram

Blink-side change: https://codereview.chromium.org/324003002/

BUG=380988
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276558

[Ilya Sherman, 2014-06-11 20:01:31]

LGTM with a suggestion:

https://codereview.chromium.org/328973002/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/328973002/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:44916: +  <int value="4" label="Unknown
/ Decode error"/>
If your Blink CL hasn't landed yet, I'd recommend making this the first bucket. 
That way, if you ever add any additional formats, "UNKNOWN" won't end up
somewhere in the middle of the list.

[Kunihiko Sakamoto, 2014-06-12 01:44:26]

https://codereview.chromium.org/328973002/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/328973002/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:44916: +  <int value="4" label="Unknown
/ Decode error"/>
On 2014/06/11 20:01:31, Ilya Sherman wrote:
> If your Blink CL hasn't landed yet, I'd recommend making this the first
bucket. 
> That way, if you ever add any additional formats, "UNKNOWN" won't end up
> somewhere in the middle of the list.

Aha, thank you for the suggestion! Done.

[Kunihiko Sakamoto, 2014-06-12 01:44:33]

The CQ bit was checked by ksakamoto@chromium.org

[commit-bot: I haz the power, 2014-06-12 01:45:18]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ksakamoto@chromium.org/328973002/20001

[commit-bot: I haz the power, 2014-06-12 07:16:35]

Change committed as 276558