Implement write methods for SparseHistogram

base/metrics/histogram_base.h

 // Copyright (c) 2012 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_BASE_H_
 #define BASE_METRICS_HISTOGRAM_BASE_H_
 
 #include <string>
 
 #include "base/base_export.h"
@@ skipping 124 matching lines @@
   // Subclasses should implement this function to make SerializeInfo work.
   virtual bool SerializeInfoImpl(Pickle* pickle) const = 0;
 
   // Writes information about the construction parameters in |params|.
   virtual void GetParameters(DictionaryValue* params) const = 0;
 
   // Writes information about the current (non-empty) buckets and their sample
   // counts to |buckets| and the total sample count to |count|.
   virtual void GetCountAndBucketData(Count* count,
                                      ListValue* buckets) const = 0;
+
+  //// Produce actual graph (set of blank vs non blank char's) for a bucket.
+  void WriteAsciiBucketGraph(double current_size,
+                             double max_size,
+                             std::string* output) const;
+
+  // Return a string description of what goes in a given bucket.
+  const std::string GetSimpleAsciiBucketRange(Sample sample) const;
+
+  // Write textual description of the bucket contents (relative to histogram).
+  // Output is the count in the buckets, as well as the percentage.
+  void WriteAsciiBucketValue(Count current,
+                             double scaled_sum,
+                             std::string* output) const;
+
  private:
   const std::string histogram_name_;
   int32 flags_;
 
   DISALLOW_COPY_AND_ASSIGN(HistogramBase);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_HISTOGRAM_BASE_H_