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/src/timer_metric.cpp

@@ -0,0 +1,33 @@
+#include "timer_metric.h"
+
+#include <stddef.h>
+#include <sys/time.h>
+
+namespace wvcdm {
+namespace metrics {
+
+void TimerMetric::Start() {
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  sec_ = tv.tv_sec;
+  usec_ = tv.tv_usec;
+}
+
+double TimerMetric::AsMs() const {
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  return usec_ > tv.tv_usec ?
+      (tv.tv_sec - sec_ - 1) * 1000.0 + (tv.tv_usec - usec_ + 1000000.0) / 1000.0 :
+      (tv.tv_sec - sec_) * 1000.0 + (tv.tv_usec - usec_) / 1000.0;
+}
+
+double TimerMetric::AsUs() const {
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  return usec_ > tv.tv_usec ?
+      (tv.tv_sec - sec_ - 1) * 1000000.0 + (tv.tv_usec - usec_ + 1000000.0) :
+      (tv.tv_sec - sec_) * 1000000.0 + (tv.tv_usec - usec_);
+}
+
+}  // namespace metrics
+}  // namespace wvcdm