Start transition the metrics library to non-static API. Use gmock in tests.

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
  */
 
 #ifndef METRICS_LIBRARY_H_
 #define METRICS_LIBRARY_H_
 
 #include <string>
 
 // TODO(sosa@chromium.org): Add testing for send methods
 
-// Library used to send metrics both Autotest and Chrome.
-class MetricsLibrary {
+class MetricsLibraryInterface {
  public:
+  virtual void Init() = 0;
+  virtual bool SendToUMA(const std::string& name, int sample,
+                         int min, int max, int nbuckets) = 0;
+  virtual bool SendEnumToUMA(const std::string& name, int sample, int max) = 0;
+  virtual ~MetricsLibraryInterface() {}
+};
+
+// Library used to send metrics to both Autotest and Chrome/UMA.
+class MetricsLibrary : public MetricsLibraryInterface {
+ public:
+  // Initializes the library.
+  void Init();
+
   // Sends 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_CUSTOM_COUNTS
   // inside Chrome (see base/histogram.h).
   //
   // |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.
+  bool SendToUMA(const std::string& name, int sample,
+                 int min, int max, int nbuckets);
+
+  // Deprecated.
   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.
+  bool SendEnumToUMA(const std::string& name, int sample, int max);
+
+  // Deprecated.
   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_ */