rename AudioSystem::newAudioSessionId()

Rename AudioSystem::newAudioSessionId() to
AudioSystem::newAudioUniqueId() as it can be used
also for I/O handles.

Bug: 12378680.
Change-Id: I611ea3b5eb57a4b0774437f477ee87dc4ccc2cc2
diff --git a/include/media/IAudioFlinger.h b/include/media/IAudioFlinger.h
index 58fb84a..82ec09c 100644
--- a/include/media/IAudioFlinger.h
+++ b/include/media/IAudioFlinger.h
@@ -176,7 +176,7 @@
 
     virtual uint32_t getInputFramesLost(audio_io_handle_t ioHandle) const = 0;
 
-    virtual int newAudioSessionId() = 0;
+    virtual audio_unique_id_t newAudioUniqueId() = 0;
 
     virtual void acquireAudioSessionId(int audioSession, pid_t pid) = 0;
     virtual void releaseAudioSessionId(int audioSession, pid_t pid) = 0;