tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index a07ff11adc515b7bb7b1314027816e89e8a8761a..6c212ee6f1a70d6bc7b33d3e00500fc38a772329 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -7328,6 +7328,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <summary>Events in Google Now component extension.</summary>
 </histogram>
 
+<histogram name="GoogleNow.MessageCenter.Displayed.NotificationsVisible"
+    units="count">
+  <owner>robliao@chromium.org</owner>
+  <owner>skare@chromium.org</owner>
+  <summary>
+    Count of the number of cards visible when the message center is shown.

[Ilya Sherman, 2014/05/06 00:33:39]

Please update this text, as I requested in previous comments.

[robliao, 2014/05/06 00:39:40]

The correct terminology is already being used. We can't add much more without
making this unnecessarily verbose.
On 2014/05/06 00:33:39, Ilya Sherman wrote:

[Ilya Sherman, 2014/05/06 00:42:41]

Might I suggest:

"""The number of Google Now cards visible when the message center (a.k.a. the
notification center) is shown."""

On 2014/05/06 00:39:40, robliao wrote:

[robliao, 2014/05/06 00:51:41]

It's the difference between this...
https://code.google.com/p/chromium/codesearch#search/&q=NotificationCenter

And this...
https://code.google.com/p/chromium/codesearch#search/&q=MessageCenter

The search results of NotificationCenter is very misleading, so that's why I
don't really want to go there.
On 2014/05/06 00:42:41, Ilya Sherman wrote:

[Ilya Sherman, 2014/05/06 01:02:32]

Code search is only one way that people might try to understand the named term. 
More likely than code search is just general awareness of Chrome's features. 
Anyone who's writing a codesearch query would probably just search for the
histogram name, "GoogleNow.MessageCenter.Displayed.NotificationsVisible", and
therefore the confusion that you mentioned doesn't seem very relevant.  OTOH,
somebody who's viewing the description on the dashboard would likely appreciate
the connection to a Chrome feature that they've heard of, as opposed to having
to guess.  How do I know?  Because I had to guess what "the message center" was,
and I'm familiar with the notifications feature that Chrome has.

Here's another way to think of it: Histogram descriptions should be
understandable to somebody who's familiar with the code.  Including both terms
makes it more likely that such a person would understand what you're referring
to.

[robliao, 2014/05/06 01:16:24]

I think we'll simply have to agree to disagree here. I've changed the term.

The search results above are simply an illustration of what terminology that's
already used and is not the only justification for using the message center as
the term here.

When constructing the summary, we should be using precise unambiguous terms that
describe the components we're working with. In the Chrome codebase, there is no
component named the Notification Center. It's called the Message Center.

I will agree this is an unfortunate diversion of the names, but that's what we
have here. As a result, everything in the codebase resolves around this
terminology. The Message Center has Message Center tests, a message center tray
bridge, a message center bubble, a message center button bar, and so forth.

Since this histogram name is used in the message center, it is appropriate that
the terminology remain consistent until the message center is renamed to the
notifications center.

The term 'notifications center' introduces inconsistency into this naming. As
such, the histogram name and summary now use two different names for the same
thing.

On 2014/05/06 01:02:32, Ilya Sherman wrote:

[Ilya Sherman, 2014/05/06 01:24:24]

I'm not saying that you shouldn't use "message center" in the summary.  Rather,
I'm encouraging you to use both terms.  You'll note that in my suggested text, I
kept "message center" as the primary term, to match your preferences, and simply
included "a.k.a. notification center" as a hint for people unfamiliar with the
term "message center".

On 2014/05/06 01:16:24, robliao wrote:

[robliao, 2014/05/06 01:29:19]

If someone is unfamiliar with both the message center and the notification
center, what do we do then?

At some point, someone is going to come across a summary of an unfamiliar
feature. Code search is there like a dictionary to help you out. 

On 2014/05/06 01:24:24, Ilya Sherman wrote:

[Ilya Sherman, 2014/05/06 04:15:36]

Again, if somebody is going to search via Code search, their best bet is to
search for the histogram name, which will return exactly one hit (I'd hope).  Do
you have any other objection to including both terms?

[robliao, 2014/05/06 17:07:23]

I still think this is the wrong thing to do, but have updated the text for the
sake of the review.

On 2014/05/06 04:15:36, Ilya Sherman wrote:

+  </summary>
+</histogram>
+
 <histogram name="GoogleUpdate.EffectivePolicy" enum="UpdatePolicy">
   <owner>gab@chromium.org</owner>
   <summary>