Track how often we would attempt to resolve non-'compliant' domain names.

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 2bb0c08e8bf28f407f7c5d54c7648401c91fb1f8..ad67519942b0b3ea9b7000ed81647a10ea1940ee 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -40028,6 +40028,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+Net.ValidAndCompliantDNSName
+<histogram name="Net.ValidAndCompliantDNSName" enum="Boolean">
+  <owner>palmer@chromium.org</owner>
+  <summary>
+    True if Net.ValidDNSName is true and if |net::IsCanonicalizedHostCompliant|

[Mark P, 2017/05/26 17:27:02]

This description doesn't sound right.  It sounds like the value emitted is
Net.ValidDNSName() && net::IsCanonicalizedHostCompliant()

Looking at the code, that's not correct.  This value is only emitted if you've
decided it's a valid DNS name, and the value emitted is
net::IsCanonicalizedHostCompliant().

Please rewrite, thanks.

Also, the histogram probably needs a better name.  The current one implies the
&& interpretation.

[palmer, 2017/05/31 20:46:23]

Done.

+    returns true. Used to see if IsCanonicalizedHostCompliant() runs afoul of
+    real websites. This histogram is recorded when converting dotted DNS names
+    into DNS query form, in preparation for issuing a DNS request.
+  </summary>
+</histogram>
+
 <histogram name="Net.ValidDNSName" enum="Boolean">
   <owner>palmer@chromium.org</owner>
   <summary>