Expose macros from base/metrics/histogram_macros.h as functions

base/metrics/histogram_macros.h

 // Copyright 2014 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.
 
 #ifndef BASE_METRICS_HISTOGRAM_MACROS_H_
 #define BASE_METRICS_HISTOGRAM_MACROS_H_
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_macros_internal.h"
 #include "base/metrics/histogram_macros_local.h"
@@ skipping 49 matching lines @@
 
 // All of these macros must be called with |name| as a runtime constant.
 
 // Used for capturing integer data with a linear bucketing scheme. This can be
 // used when you want the exact value of some small numeric count, with a max of
 // 100 or less. If you need to capture a range of greater than 100, we recommend
 // the use of the COUNT histograms below.
 
 // Sample usage:
 //   UMA_HISTOGRAM_EXACT_LINEAR("Histogram.Linear", count, 10);
-#define UMA_HISTOGRAM_EXACT_LINEAR(name, sample, value_max)                    \
-    UMA_HISTOGRAM_ENUMERATION(name, sample, value_max+1)
+#define UMA_HISTOGRAM_EXACT_LINEAR(name, sample, value_max) \
+  UMA_HISTOGRAM_ENUMERATION(name, sample, value_max)

[wychen, 2016/11/14 23:56:11]

Ah. I was confused why we have to +1 twice.

 
 // Used for capturing basic percentages. This will be 100 buckets of size 1.
 
 // Sample usage:
 //   UMA_HISTOGRAM_PERCENTAGE("Histogram.Percent", percent_as_int);
 #define UMA_HISTOGRAM_PERCENTAGE(name, percent_as_int)                         \
     UMA_HISTOGRAM_ENUMERATION(name, percent_as_int, 101)
 
 //------------------------------------------------------------------------------
 // Count histograms. These are used for collecting numeric data. Note that we
@@ skipping 191 matching lines @@
 // |custom_ranges|. See comments above CustomRanges::FactoryGet about the
 // requirement of |custom_ranges|. You can use the helper function
 // CustomHistogram::ArrayToCustomRanges to transform a C-style array of valid
 // sample values to a std::vector<int>.
 #define UMA_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges)          \
     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample),                          \
         base::CustomHistogram::FactoryGet(name, custom_ranges,                 \
             base::HistogramBase::kUmaTargetedHistogramFlag))
 
 #endif  // BASE_METRICS_HISTOGRAM_MACROS_H_