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: Iede35e73e9007df13254edaa5877cb4832b28646

include/media/hardware/CryptoAPI.h

@@ -14,7 +14,9 @@
  * limitations under the License.
  */
 
+#include <media/stagefright/MediaErrors.h>
 #include <utils/Errors.h>
+#include <utils/Vector.h>
 
 #ifndef CRYPTO_API_H_
 
@@ -71,6 +73,16 @@ struct CryptoPlugin {
 
     virtual void notifyResolution(uint32_t /* width */, uint32_t /* height */) {}
 
+    // A MediaDrm session may be associated with a MediaCrypto session.  The
+    // associated MediaDrm session is used to load decryption keys
+    // into the crypto/drm plugin.  The keys are then referenced by key-id
+    // in the 'key' parameter to the decrypt() method.
+    // Should return NO_ERROR on success, ERROR_DRM_SESSION_NOT_OPENED if
+    // the session is not opened and a code from MediaErrors.h otherwise.
+    virtual status_t setMediaDrmSession(const Vector<uint8_t> & /*sessionId */) {
+        return ERROR_UNSUPPORTED;
+    }
+
     // If the error returned falls into the range
     // ERROR_DRM_VENDOR_MIN..ERROR_DRM_VENDOR_MAX, errorDetailMsg should be
     // filled in with an appropriate string.