Use audio_session_t consistently

Bug: 27562099
Change-Id: I328d8226191386b163f2ace41233607294c50dcd
diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index 4de55a2..9e0e98b 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -213,7 +213,7 @@
                                     callback_t cbf       = NULL,
                                     void* user           = NULL,
                                     uint32_t notificationFrames = 0,
-                                    int sessionId        = AUDIO_SESSION_ALLOCATE,
+                                    audio_session_t sessionId  = AUDIO_SESSION_ALLOCATE,
                                     transfer_type transferType = TRANSFER_DEFAULT,
                                     const audio_offload_info_t *offloadInfo = NULL,
                                     int uid = -1,
@@ -242,7 +242,7 @@
                                     callback_t cbf      = NULL,
                                     void* user          = NULL,
                                     uint32_t notificationFrames = 0,
-                                    int sessionId       = AUDIO_SESSION_ALLOCATE,
+                                    audio_session_t sessionId   = AUDIO_SESSION_ALLOCATE,
                                     transfer_type transferType = TRANSFER_DEFAULT,
                                     const audio_offload_info_t *offloadInfo = NULL,
                                     int uid = -1,
@@ -287,7 +287,7 @@
                             uint32_t notificationFrames = 0,
                             const sp<IMemory>& sharedBuffer = 0,
                             bool threadCanCallJava = false,
-                            int sessionId       = AUDIO_SESSION_ALLOCATE,
+                            audio_session_t sessionId  = AUDIO_SESSION_ALLOCATE,
                             transfer_type transferType = TRANSFER_DEFAULT,
                             const audio_offload_info_t *offloadInfo = NULL,
                             int uid = -1,
@@ -583,7 +583,7 @@
      * Returned value:
      *  AudioTrack session ID.
      */
-            int    getSessionId() const { return mSessionId; }
+            audio_session_t getSessionId() const { return mSessionId; }
 
     /* Attach track auxiliary output to specified effect. Use effectId = 0
      * to detach track from effect.
@@ -959,7 +959,7 @@
 
     bool                    mDoNotReconnect;
 
-    int                     mSessionId;
+    audio_session_t         mSessionId;
     int                     mAuxEffectId;
 
     mutable Mutex           mLock;