Add a field indicating online vs offline licenses.

Import of http://go/wvgerrit/68188

This adds an attribute to metrics indicating if the license was online
or offline.

Also, added a unit test for CdmEngineMetricsImpl.

Test: Unit tests. GPlay manual. GTS tests.
Bug: 115523917

Change-Id: Id315c643048914a2c51904451f9665987bc87eb7

libwvdrmengine/cdm/core/test/test_base.cpp

@@ -610,8 +610,10 @@ void TestLicenseHolder::SignAndLoadLicense() {
   signed_response.SerializeToString(&response_data);
 
   CdmKeySetId key_set_id;
+  CdmLicenseType license_type;  // Required for AddKey. Result value ignored.
   EXPECT_EQ(KEY_ADDED,
-            cdm_engine_->AddKey(session_id_, response_data, &key_set_id));
+            cdm_engine_->AddKey(session_id_, response_data,
+                                &license_type, &key_set_id));
 }
 
 void TestLicenseHolder::DeriveKeysFromSessionKey() {