Revise a few metrics and add unit tests.

This is a merge of Widevine cl 39040.

A few of the metrics were not implemented, or implemented incorrectly in
O MR1. This cleans them up

Bug: 64001676

Test: Re-ran unit tests and added some additional tests. GPlay Movies check.

Change-Id: I1e8bcc36fecd76e72d853306075bc46d82f45161

libwvdrmengine/cdm/metrics/src/value_metric.cpp

@@ -110,6 +110,14 @@ void Serialize<OEMCryptoInitializationMode>(
   serializer->SetInt32(metric_name, value);
 }
 
+template<>
+void Serialize<CdmUsageSupportType>(
+    MetricSerializer* serializer,
+    const std::string& metric_name,
+    const CdmUsageSupportType& value) {
+  serializer->SetInt32(metric_name, value);
+}
+
 }  // namespace impl
 }  // namespace metrics
 }  // namespace wvcdm