Allow UmaHistogramEnumeration to be used with enum classes.

base/metrics/histogram_functions.h

Index: base/metrics/histogram_functions.h
diff --git a/base/metrics/histogram_functions.h b/base/metrics/histogram_functions.h
index 58fc30173c6ea17480175440202c384b96661261..851171e4a5db3a6709e6261c3f1d5727d20ae4a1 100644
--- a/base/metrics/histogram_functions.h
+++ b/base/metrics/histogram_functions.h
@@ -43,7 +43,8 @@ template <typename T>
 void UmaHistogramEnumeration(const std::string& name, T sample, T max) {
   static_assert(std::is_enum<T>::value,
                 "Non enum passed to UmaHistogramEnumeration");
-  return UmaHistogramExactLinear(name, static_cast<int>(sample), max);
+  return UmaHistogramExactLinear(name, static_cast<int>(sample),

[dcheng, 2017/04/05 17:12:13]

Nit: it might be nice to DCHECK that sample and max are in range of int.

[benwells, 2017/04/06 07:30:01]

Hmmm .... OK. Not the simplest nit I've seen, or maybe I'm being dumb.

+                                 static_cast<int>(max));
 }
 
 // For adding boolean sample to histogram.