Direct api to the native media player.

MediaPlayer.java has 3 new methods:
* newRequest creates a Parcel that can be used to send data to the
  native player using invoke.
* invoke issues synchronous calls to the native player using opaque
  parcels for the request and reply.

IMediaPlayer.h has 1 new abstract method:
* invoke

The Midi and Vorbis players have a stub for these. So far only PV
makes use of that new feature.

To avoid any copy overhead, the JNI interface uses Parcel as a java
object (no serialization/copy happens at the JNI layer).

The remote interface token is inserted when the Parcel is constructed
in java. That way the parcel is already routable when it reaches
 IMediaPlayer.cpp (proxy). No extra copy is needed there.
diff --git a/include/media/IMediaPlayer.h b/include/media/IMediaPlayer.h
index 2c4bc2a..85aeb30 100644
--- a/include/media/IMediaPlayer.h
+++ b/include/media/IMediaPlayer.h
@@ -23,6 +23,7 @@
 
 namespace android {
 
+class Parcel;
 class ISurface;
 
 class IMediaPlayer: public IInterface
@@ -45,6 +46,14 @@
     virtual status_t        setAudioStreamType(int type) = 0;
     virtual status_t        setLooping(int loop) = 0;
     virtual status_t        setVolume(float leftVolume, float rightVolume) = 0;
+
+    // Invoke a generic method on the player by using opaque parcels
+    // for the request and reply.
+    // @param request Parcel that must start with the media player
+    // interface token.
+    // @param[out] reply Parcel to hold the reply data. Cannot be null.
+    // @return OK if the invocation was made. PERMISSION_DENIED otherwise.
+    virtual status_t        invoke(const Parcel& request, Parcel *reply) = 0;
 };
 
 // ----------------------------------------------------------------------------
@@ -61,4 +70,3 @@
 }; // namespace android
 
 #endif // ANDROID_IMEDIAPLAYER_H
-