Added CDM support for Watermarking reporting.

[ Merge of http://go/wvgerrit/148552 ]

Extended the CDM layer to report OEMCrypto's watermarking support.
The reporting of watermarking comes in three (3) mechanisms:
1) ClientCapabilities in license requests
2) CryptoSession metrics when queried to OEMCrypto
3) String property query by apps

If OEMCrypto implementents OEMCrypto_GetWatermarkingSupport(), then
the reported watermarking support by the CDM will match that of
OEMCrypto.

If OEMCrypto does not implement OEMCrypto_GetWatermarkingSupport()
or an error occurs, it is assumed that OEMCrypto does not support
watermarking, and the CDM will report "Not Supported".

Bug: 226443788
Test: run_x86_64_tests request_license_test and license_unittest
Change-Id: Id929a356c395e6bcf45d371ee6887eec40d35329

libwvdrmengine/cdm/metrics/include/metrics_collections.h

@@ -297,6 +297,7 @@ class CryptoMetrics {
       oemcrypto_generate_certificate_key_pair_;
   EventMetric<kOemCryptoResultFieldNumber, OEMCryptoResult>
       oemcrypto_install_oem_private_key_;
+  ValueMetric<int> oemcrypto_watermarking_support_;
 };  // class CryptoMetrics
 
 // This class contains session-scoped metrics. All properties and