File util, generic crypto, and key query

This CL merges several CLs from the widevine repo:

http://go/wvgerrit/18012 Add support for querying allowed usage for key.
http://go/wvgerrit/17971 Add per-origin storage.
http://go/wvgerrit/18152 Add OEMCrypto's generic crypto operations to CDM.
http://go/wvgerrit/17911 QueryKeyControlInfo => QueryOemCryptoSessionId

Note: numbering in wv_cdm_types.h was added in this CL and will be
back ported to wvgerrit in a future CL.

Change-Id: Idb9e9a67e94f62f25dc16c5307f75a08b3430b64

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -1293,7 +1293,7 @@ class OEMCryptoSessionTestsDecryptTests
   }
 
   void TestDecryptCENC(const vector<uint8_t>& key,
-                       const vector<uint8_t>& encryptionIv,
+                       const vector<uint8_t>& /* encryptionIv */,
                        const vector<uint8_t>& encryptedData,
                        const vector<uint8_t>& unencryptedData) {
     OEMCryptoResult sts;