1. Add test for https://src.chromium.org/viewvc/chrome?view=rev&revision=149541

base/metrics/histogram.cc

Index: base/metrics/histogram.cc
===================================================================
--- base/metrics/histogram.cc	(revision 149541)
+++ base/metrics/histogram.cc	(working copy)
@@ -883,14 +883,15 @@
 // static
 bool CustomHistogram::ValidateCustomRanges(
     const vector<Sample>& custom_ranges) {
-  if (custom_ranges.size() < 1)
-    return false;
+  int valid_ranges = 0;

[jar (doing other things), 2012/08/03 21:53:42]

Suggest use boolean:
bool valid_ranges = false;

then set where you would increment.

[kaiwang, 2012/08/03 22:15:53]

Done.

   for (size_t i = 0; i < custom_ranges.size(); i++) {
     Sample s = custom_ranges[i];

[jar (doing other things), 2012/08/03 21:53:42]

nit: (on existing code): Please use |sample| instead of s

[kaiwang, 2012/08/03 22:15:53]

Done.

     if (s < 0 || s > HistogramBase::kSampleType_MAX - 1)
       return false;
+    if (s != 0)
+      valid_ranges++;
   }
-  return true;
+  return valid_ranges > 0;
 }
 
 // static