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 dce89b4b973c7c79a1cdb76bea0b40d67a63a8dc..2092b6138dd203383e9535c2a0769245b1675899 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -20092,6 +20092,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="PasswordManager.AutofillResultsFiltered" enum="Boolean">
+  <owner>gcasto@chromium.org</owner>
+  <owner>vabr@chromium.org</owner>
+  <summary>
+    If autofill results were not shown, e.g. the sync credential was removed.

[Ilya Sherman, 2014/08/12 02:17:34]

There are other reasons that IgnoreResult() might return |true|, resulting in
autofill results not being shown -- right?  Perhaps it makes sense to have a
more focused histogram, to measure specifically the case that the sync
credential was removed?

[Garrett Casto, 2014/08/13 20:34:41]

There are other reasons that IgnoreResult might return true (e.g. bad SSL cert),
but this histogram will only be get a yes if it's because of the client
requesting it be blocked. At the moment this is only due to sync credential
issues. 

I was a little torn about this. I first wanted to put the histogram in the
client, but if you do that then you will get one report per filtered credential
instead of one per Autofill experience (which is really what matters). I could
have also made the API more specific about why it's filtering, but I wanted to
leave open the option of changing what exactly we filter without changing the
function defintion. Does this seem reasonable to you?

[Ilya Sherman, 2014/08/13 20:48:14]

We could have an additional method on the client for reporting metrics.  I'm
worried that if we leave the code as is, it can easily evolve to start
conflating multiple different events into this one histogram, without anyone
ever noticing the problem.

[Garrett Casto, 2014/08/13 23:12:54]

Added a reporting mechanism.

+  </summary>
+</histogram>
+
 <histogram name="PasswordManager.BlacklistedSites">
   <owner>dubroy@chromium.org</owner>
   <owner>vabr@chromium.org</owner>