Avoid re-initializing CDM properties

[ Merge of http://go/wvgerrit/35405 ]

Devices that launch with android O as their first release have
SPOIDs (Stable Per-Origin IDentifier) enabled. This results
in multiple CdmEngine instances, one for each CDM identifier
(that differ by app package name possibly origin).

Each time a CDMEngine object is created, the CDM properties are
reinitialized. This causes certain property information stored on
a session basis (privacy mode, service certificate, session sharing)
to be lost. Since Query calls are not app specific, they can often
result in CdmEngine object creation, causing existing sessions to
lose associated property information. This can be avoided by
initializing CDM proerpties only once.

Bug: 65732345

Test: WV unit/integration tests
Test: GTS tests
Test: Playback using Google Play, Netflix and YT Live

Change-Id: Ic121f322ed6e45e2033964e6439c026de2401b4c

libwvdrmengine/cdm/core/src/cdm_engine.cpp

@@ -69,8 +69,8 @@ CdmEngine::CdmEngine(FileSystem* file_system, const std::string& spoid)
       usage_session_(NULL),
       last_usage_information_update_time_(0) {
   assert(file_system);
-  Properties::Init();
   if (!seeded_) {
+    Properties::Init();
     srand(clock_.GetCurrentTime());
     seeded_ = true;
   }