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 db3356fd21c8b3f2c97f14929ce5fdd4acc12b81..c7b98e27fb127749c07f8c242a9549b36ccaf237 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -11285,6 +11285,23 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="History.FaviconDatabaseAdvancedMetricsTime" units="ticks">
+  <owner>rogerm@google.com</owner>
+  <summary>
+    The wallclock time taken to gather favicon database metrics.

[pkotwicz, 2015/03/27 15:45:25]

Nit: "wallclock" -> "wall clock"

[Roger McFarlane (Chromium), 2015/03/30 17:35:48]

Done.

More precisely, "wall-clock"... which is consistently used throughout this file.

+  </summary>
+</histogram>
+
+<histogram name="History.FaviconDatabaseSizeMB" units="MB">
+  <owner>rogerm@google.com</owner>
+  <summary>
+    Size of the Favicons database in MB. This is calculated as the number of
+    pages consumed by the database multiplied by the page size (floored to the
+    next losest MB). So, it does not quite represent the amount of actual data

[pkotwicz, 2015/03/27 15:45:25]

Nit: I think you can remove "(floored to next losest MB)". I think that the
rounding is an implementation detail.

[Roger McFarlane (Chromium), 2015/03/30 17:35:49]

Done.

+    that is in the database.
+  </summary>
+</histogram>
+
 <histogram name="History.FaviconsRecoveredPercentage" units="%">
   <owner>rpop@google.com</owner>
   <summary>
@@ -11322,6 +11339,48 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="History.NumFaviconBitmapsInDB">
+  <owner>rogerm@google.com</owner>
+  <summary>
+    The total number of favicon bitmaps (of all sizes) cached in a user's
+    Favicon database. A given favicon file/URL may contain multiple bitmap
+    assets at different resolutions/sizes.

[pkotwicz, 2015/03/27 15:45:25]

How about:
"The total number of favicon bitmaps (of all sizes) cached in a user's Favicon
database. A given favicon URL may be associated with multiple bitmaps (of
different sizes)"

[Roger McFarlane (Chromium), 2015/03/30 17:35:48]

Done.

+  </summary>
+</histogram>
+
+<histogram name="History.NumFaviconsInDB">
+  <owner>rogerm@google.com</owner>
+  <summary>
+    The total number of favicon files (by favicon URL) being tracked in a user's
+    Favicon database. Note that this metric tracks knowledge of an favicon URL,
+    not whether or not the assets behind that URL are in the favicon cache; see
+    Hisory.NumFaviconBitmapsInDB for that.

[pkotwicz, 2015/03/27 15:45:25]

How about:
"The total number of favicon URLs (e.g. http://www.google.com/favicon.ico)
tracked in a user's Favicon database. This metric tracks knowledge of a favicon
URL not whether there are cached bitmaps for that favicon URL. See
History.NumFaviconBitmapsInDB for that."

Aside: We currently should not have an entry in the "favicons" table without any
associated entries in the "favicon_bitmaps" table

[Roger McFarlane (Chromium), 2015/03/30 17:35:48]

Done.

+  </summary>
+</histogram>
+
+<histogram name="History.NumLargeFaviconBitmapsInDB">
+  <owner>rogerm@google.com</owner>
+  <summary>
+    The total number of large (i.e., apple touch and similar) favicon bitmaps
+    cached in a user's Favicon database. A given favicon file/URL may contain
+    multiple bitmap assets at different resolutions/sizes. Note that this is a
+    subset of History.NumFaviconBitmapsInDB, which includes all sizes in its
+    count.

[pkotwicz, 2015/03/27 15:45:25]

Can you please update the description to match the SQL query?
On Android, non-touch large favicons (of type FAVICON) are stored to the Favicon
database

[Roger McFarlane (Chromium), 2015/03/30 17:35:48]

Updated this to just track the number of large (by pixel size) icons in the
dababase.

+  </summary>
+</histogram>
+
+<histogram name="History.NumLargeFaviconsInDB">
+  <owner>rogerm@google.com</owner>
+  <summary>
+    The total number of large (i.e., apple touch and similar) favicon files
+    being tracked in a user's Favicon database. Note that this is a subset of
+    History.NumFaviconsInDB, which includes all sizes in its count. Further note
+    that this metric tracks knowledge of a large favicon URL, not whether or not
+    the assets behind that URL are in the favicon cache; see
+    History.NumLargeFaviconBitmapsInDB for that.
+  </summary>
+</histogram>
+
 <histogram name="History.TopSitesRecoveredPercentage" units="%">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>