Add Bookmarks.BookmarksInFolder histogram to bookmark manager.

chrome/browser/resources/bookmark_manager/js/bmm/bookmark_list.js

Index: chrome/browser/resources/bookmark_manager/js/bmm/bookmark_list.js
diff --git a/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_list.js b/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_list.js
index 4914b68e8c26e355cd7f83febb7473aebaccd6e4..87be223908241ddbf0e71266d25e2616434a0eb4 100644
--- a/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_list.js
+++ b/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_list.js
@@ -149,6 +149,14 @@ cr.define('bmm', function() {
 
       this.fixWidth_();
       cr.dispatchSimpleEvent(this, 'load');
+      chrome.metricsPrivate.recordValue({
+        'metricName': 'Bookmarks.BookmarksInFolder',
+        'type': chrome.metricsPrivate.MetricTypeType.HISTOGRAM_LOG,
+        'min': 0,
+        'max': 200,

[Dan Beam, 2016/11/16 01:26:51]

wait, why a max of 200?

[Alexei Svitkine (slow), 2016/11/16 01:34:09]

Suggest using equivalent of UMA_HISTOGRAM_COUNTS_1000().

That is, min:1, max:1000, buckets:50

You can also mention that macro in the comment above.

(Note: The min:1 will still give you a 0-1 bucket since there's always a 0
bucket.)

[calamity, 2016/11/16 01:57:46]

Done.

+        'buckets': 10
+      }, this.dataModel.length);
+      console.log(this.dataModel.length);

[Dan Beam, 2016/11/16 01:26:51]

nit: remove the log()

[calamity, 2016/11/16 01:57:46]

Done.

     },
 
     /**