Add Sandbox ID support

Merge from master branch of Widevine repo of http://go/wvgerrit/66078
Merge from oemcrypto-v15 branch of Widevine repo of http://go/wvgerrit/64022

This CL updates OEMCrypto ref code, unit tests, and core code for
setting the sandbox id before initializing OEMCrypto.

Test: unit tests only
Test: tested as part of http://go/ag/5501993
Bug: 115834255
Change-Id: Id9831680fe4db1c69413815931cae4bc80df0c01

libwvdrmengine/cdm/src/properties_android.cpp

@@ -151,6 +151,17 @@ bool Properties::GetOEMCryptoPath(std::string* library_name) {
   return true;
 }
 
+bool Properties::GetSandboxId(std::string* /* sandbox_id */) {
+  // TODO(fredgc): If needed, we could support android running on a VM by
+  // reading the sandbox ID from the file system.  If the file system
+  // does not have a sandbox id, we would generate a random
+  // one. Another option is to have sandbox id be a system property.
+  // However, that is enough work not to do it pre-emptively.  This
+  // TODO is just to let future coders know that the framework is in
+  // place, and should be pretty easy to plumb.
+  return false;
+}
+
 bool Properties::AlwaysUseKeySetIds() {
   return false;
 }