Add a default implementation in metrics_default.cc of histograms methods in system_wrappers/interface/metrics.h.
Updated tests to use the default implementation and removed the test implementation (webrtc/test/histograms.h).
BUG=
Review-Url: https://codereview.webrtc.org/1915523002
Cr-Commit-Position: refs/heads/master@{#12829}
diff --git a/webrtc/system_wrappers/include/metrics_default.h b/webrtc/system_wrappers/include/metrics_default.h
new file mode 100644
index 0000000..e4b790b
--- /dev/null
+++ b/webrtc/system_wrappers/include/metrics_default.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_SYSTEM_WRAPPERS_INCLUDE_METRICS_DEFAULT_H_
+#define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_METRICS_DEFAULT_H_
+
+#include <map>
+#include <memory>
+#include <string>
+
+namespace webrtc {
+namespace metrics {
+
+struct SampleInfo {
+ SampleInfo(const std::string& name, int min, int max, size_t bucket_count);
+ ~SampleInfo();
+
+ const std::string name;
+ const int min;
+ const int max;
+ const size_t bucket_count;
+ std::map<int, int> samples; // <value, # of events>
+};
+
+// Enables collection of samples.
+// This method should be called before any other call into webrtc.
+void Enable();
+
+// Gets histograms and clears all samples.
+void GetAndReset(
+ std::map<std::string, std::unique_ptr<SampleInfo>>* histograms);
+
+// Functions below are mainly for testing.
+
+// Clears all samples.
+void Reset();
+
+// Returns the number of times the |sample| has been added to the histogram.
+int NumEvents(const std::string& name, int sample);
+
+// Returns the total number of added samples to the histogram.
+int NumSamples(const std::string& name);
+
+// Returns the minimum sample value (or -1 if the histogram has no samples).
+int MinSample(const std::string& name);
+
+} // namespace metrics
+} // namespace webrtc
+
+#endif // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_METRICS_DEFAULT_H_