Add build info API to OEMCrypto

Merge from master branch of Widevine repo of http://go/wvgerrit/66065
Merge from oemcrypto-v15 branch of Widevine repo of http://go/wvgerrit/63080

This is for the reference code, the unit tests, and the oemcrypto adapter.

Bug: 116414218
Test: unit tests
Test: tested as part of http://go/ag/5501993

Change-Id: I05a631f6cfcf1584a748b3a0c9ae48633893589f

libwvdrmengine/oemcrypto/ref/src/oemcrypto_ref.cpp

@@ -1148,6 +1148,10 @@ extern "C" uint32_t OEMCrypto_GetAnalogOutputFlags() {
   return crypto_engine->analog_output_flags();
 }
 
+extern "C" const char* OEMCrypto_BuildInformation() {
+  return "OEMCrypto Ref Code " __DATE__ " " __TIME__;
+}
+
 extern "C" bool OEMCrypto_SupportsUsageTable() {
   if (!crypto_engine) {
     LOGE("OEMCrypto_SupportsUsageTable: OEMCrypto Not Initialized.");