Fixes widevine metrics proto serialization

Changes to a much more efficient and more reusable protobuf format for
metrics.

Test: Widevine tests, Google Play and MediaDrm CTS test.
Bug: 73724218

Change-Id: I3299051d7a16bcd7758c8f272415ca40e10c1313

libwvdrmengine/cdm/Android.mk

@@ -46,6 +46,7 @@ LOCAL_SRC_FILES := \
     $(CORE_SRC_DIR)/sublicense_key_session.cpp \
     $(CORE_SRC_DIR)/usage_table_header.cpp \
     $(SRC_DIR)/wv_content_decryption_module.cpp \
+    $(METRICS_SRC_DIR)/attribute_handler.cpp \
     $(METRICS_SRC_DIR)/counter_metric.cpp \
     $(METRICS_SRC_DIR)/distribution.cpp \
     $(METRICS_SRC_DIR)/event_metric.cpp \