Switch to the new CustomHistogram::ArrayToCustomRanges() utility

base/metrics/histogram.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 // See header file for details and examples.
 
 #include "base/metrics/histogram.h"
@@ skipping 928 matching lines @@
 Histogram::ClassType CustomHistogram::histogram_type() const {
   return CUSTOM_HISTOGRAM;
 }
 
 // static
 std::vector<Histogram::Sample> CustomHistogram::ArrayToCustomRanges(
     const Sample* values, size_t num_values) {
   std::vector<Sample> all_values;
   for (size_t i = 0; i < num_values; ++i) {
     Sample value = values[i];
+    DCHECK_GE(value, 0);  // You must use positive sample values.

[jar (doing other things), 2011/05/24 18:10:07]

This is a good idea (I love DCHECKS).  It would be better to push this down into
the constructor, and assert that we never get fed a negative number.  That would
catch more problems (since it is at a lower level).  I'd even be ok with making
this a CHECK() (release time assertion), as I'm not sure how well the code would
handle negative values during searches. I'm pretty sure the first (least) value
in the range MUST be 0, which would break if some negative values were sorted
into the mix

[Jói, 2011/05/24 18:27:31]

I moved it to Histogram::SetBucketRange. Let me know if that is wrong.

I left it as a DCHECK to match the other checks that are in place in the class.

     all_values.push_back(value);
 
     // Ensure that a guard bucket is added. If we end up with duplicate
     // values, FactoryGet will take care of removing them.
     all_values.push_back(value + 1);
   }
   return all_values;
 }
 
 CustomHistogram::CustomHistogram(const std::string& name,
@@ skipping 178 matching lines @@
 }
 
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;
 // static
 bool StatisticsRecorder::dump_on_exit_ = false;
 
 }  // namespace base