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/timer_metric.h

@@ -0,0 +1,24 @@
+#ifndef WVCDM_METRICS_TIMER_METRIC_H_
+#define WVCDM_METRICS_TIMER_METRIC_H_
+
+#include <stdint.h>
+
+namespace wvcdm {
+namespace metrics {
+
+class TimerMetric {
+
+ public:
+  void Start();
+  double AsMs() const;
+  double AsUs() const;
+
+ private:
+  double sec_;
+  double usec_;
+
+};
+
+}  // namespace metrics
+}  // namespace wvcdm
+#endif