Add SSL Connection Error UMA.

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 6b9188a6fcd9baecf616ba08e3afb8660b463272..9b95f56ad18f0c6a378fa2faee5585281e65b069 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -19142,6 +19142,21 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <summary>The SSL/TLS cipher suite that was negotiated.</summary>
 </histogram>
 
+<histogram name="Net.SSL_Connection_Error" enum="NetErrorCodes">
+  <owner>agl@chromium.org</owner>
+  <summary>
+    Counts of specific error codes returned when opening an SSL connection.
+  </summary>
+</histogram>
+
+<histogram name="Net.SSL_Connection_Error_Google" enum="NetErrorCodes">

[Alexei Svitkine (slow), 2015/01/29 16:51:24]

I don't see where this is logged?

[jeremyim, 2015/01/29 17:40:43]

This will come in https://codereview.chromium.org/869393005 (or a variant
thereof).

+  <owner>agl@chromium.org</owner>
+  <summary>
+    Counts of specific error codes returned when opening an SSL connection on
+    google.com and any subdomain of it.
+  </summary>
+</histogram>
+
 <histogram name="Net.SSL_Connection_Latency" units="milliseconds">
   <obsolete>
     Replaced by Net.SSL_Connection_Latency_2 on 2014-10-21.