Streamline cast certificate loading

This CL adds special code to create a session and sign a
message with an RSA key without initializing the full session.

This is to fix:
b/16130551 Molly does not show up in CAST device list

Change-Id: I4a14b312ef67e666c7c9504fe8135c6924be4c0d

libwvdrmengine/mediadrm/include/WVGenericCryptoInterface.h

@@ -8,6 +8,8 @@
 #include <stdint.h>
 
 #include "OEMCryptoCENC.h"
+#include "media/stagefright/foundation/ABase.h"
+#include "utils/Vector.h"
 
 namespace wvdrm {
 
@@ -57,6 +59,14 @@ class WVGenericCryptoInterface {
                                     algorithm, signature, signature_length);
   }
 
+  virtual OEMCryptoResult signRSA(const uint8_t* wrapped_rsa_key,
+                                  size_t wrapped_rsa_key_length,
+                                  const uint8_t* message,
+                                  size_t message_length,
+                                  android::Vector<uint8_t>& signature,
+                                  RSA_Padding_Scheme padding_scheme);
+
+
   virtual OEMCryptoResult loadDeviceRSAKey(OEMCrypto_SESSION session,
                                            const uint8_t* wrapped_rsa_key,
                                            size_t wrapped_rsa_key_length) {