Widevine Metrics System

This change is the complete Widevine metrics system. It will
measure and record runtime information about what is happening
in the CDM - such as errors and throughput.

Bug: 33745339
Bug: 26027857
Change-Id: Ic9a82074f1e2b72c72d751b235f8ae361232787d

libwvdrmengine/cdm/metrics/include/metrics_front_end.h

@@ -0,0 +1,56 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+
+#ifndef WVCDM_METRICS_METRICS_FRONT_END_H_
+#define WVCDM_METRICS_METRICS_FRONT_END_H_
+
+#include <map>
+
+#include "report.h"
+#include "timer_metric.h" /* needed for the macro */
+
+namespace wvcdm {
+namespace metrics {
+
+class MetricsFrontEnd {
+
+ public:
+
+  MetricsFrontEnd(Report* root);
+
+  MetricNotification* CreateSubscriber();
+
+  static MetricsFrontEnd& Instance();
+  static void OverrideInstance(MetricsFrontEnd* instance);
+
+ private:
+
+  static MetricsFrontEnd* instance_;
+
+  Report* root_;
+
+  /* Disallow copy and assign. */
+  MetricsFrontEnd(const MetricsFrontEnd&);
+  void operator=(const MetricsFrontEnd&);
+};
+
+} // namespace metrics
+} // namespace wvcdm
+
+#define MFE wvcdm::metrics::MetricsFrontEnd::Instance()
+
+#define M_RECORD(GROUP, METRIC, ...) \
+  if ( GROUP ) { \
+    ( GROUP ) -> METRIC . Record( __VA_ARGS__ ); \
+  }
+
+#define M_TIME(CALL, GROUP, METRIC, ...) \
+  if ( GROUP ) { \
+    wvcdm::metrics::TimerMetric timer; \
+    timer.Start(); \
+    CALL; \
+    ( GROUP ) -> METRIC . Record(timer.AsUs(), ##__VA_ARGS__ ); \
+  } else { \
+    CALL; \
+  }
+
+#endif