Add "Model Year" to list of CDM identification properties

(This is a merge of http://go/wvgerrit/138969.)

Provisioning 4.0 on CE CDM requires not only the make & model but the
model year in order to relate a device back to its system ID. This patch
adds model year to the list of properties that partners must provide as
client identification.

As no equivalent field exists for Android, this property is not
provided on Android platforms.

Bug: 206453352
Test: x86-64
Change-Id: I0764d67fec54fa9a0c65074e68f3ee02de1e7820

libwvdrmengine/cdm/src/properties_android.cpp

@@ -71,6 +71,10 @@ bool Properties::GetModelName(std::string* model_name) {
   return GetAndroidProperty("ro.product.model", model_name);
 }
 
+bool Properties::GetModelYear(std::string* /*model_year*/) {
+  return false;  // Not implemented on Android
+}
+
 bool Properties::GetArchitectureName(std::string* arch_name) {
   if (!arch_name) {
     LOGW("Properties::GetArchitectureName: Invalid parameter");