Add a method to associate MediaDrm session with MediaCrypto

Previously, to associate a MediaDrm session with MediaCrypto,
the MediaDrm sessionId was passed as initData to the MediaCrypto
constructor.  This is not ideal for two reasons: it's pretty
obscure and you can't change the association without tearing
down the MediaCodec/MediaCrypto and starting all over.  Use
cases like key rotation require being able to update the
MediaDrm session post-construction.  This CL addresses both of
these issues.

bug: 19570317
Change-Id: Ieb32d04d61742fc1dee2105dd904690d44c46c7b
diff --git a/media/libmediaplayerservice/Crypto.cpp b/media/libmediaplayerservice/Crypto.cpp
index e768772..f639193 100644
--- a/media/libmediaplayerservice/Crypto.cpp
+++ b/media/libmediaplayerservice/Crypto.cpp
@@ -268,4 +268,14 @@
     }
 }
 
+status_t Crypto::setMediaDrmSession(const Vector<uint8_t> &sessionId) {
+    Mutex::Autolock autoLock(mLock);
+
+    status_t result = NO_INIT;
+    if (mInitCheck == OK && mPlugin != NULL) {
+        result = mPlugin->setMediaDrmSession(sessionId);
+    }
+    return result;
+}
+
 }  // namespace android