Add support for linear/enumeration histograms.

src/platform/metrics/metrics_library.h

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /*
  * metrics_library.h
  *
  *  Created on: Dec 1, 2009
  *      Author: sosa
  */
@@ skipping 15 matching lines @@
   //
   // |sample| is the sample value to be recorded (|min| <= |sample| < |max|).
   // |min| is the minimum value of the histogram samples (|min| > 0).
   // |max| is the maximum value of the histogram samples.
   // |nbuckets| is the number of histogram buckets.
   // [0,min) is the implicit underflow bucket.
   // [|max|,infinity) is the implicit overflow bucket.
   static bool SendToChrome(const std::string& name, int sample,
                            int min, int max, int nbuckets);
 
+  // Sends linear histogram data to Chrome for transport to UMA and
+  // returns true on success. This method results in the equivalent of
+  // an asynchronous non-blocking RPC to UMA_HISTOGRAM_ENUMERATION
+  // inside Chrome (see base/histogram.h).
+  //
+  // |sample| is the sample value to be recorded (1 <= |sample| < |max|).
+  // |max| is the maximum value of the histogram samples.
+  // 0 is the implicit underflow bucket.
+  // [|max|,infinity) is the implicit overflow bucket.
+  static bool SendEnumToChrome(const std::string& name, int sample, int max);
+
   // Sends to Autotest and returns true on success.
   static bool SendToAutotest(const std::string& name, int value);
 };
 
 #endif /* METRICS_LIBRARY_H_ */