audio: new routing strategies and stream types

Added new routing strategies and stream type for internal use
by audio policy manager and audio flinger:
- One for accessibility to allow different routing than media
- One for re-routing (remote submix) in preparation of dynamic
policies
- Added stream type for "internal" audio flinger tracks used
for audio patches and duplication.

Bug: 18067208.
Change-Id: I88f884b552e51e4a49c29125e5a1204cf58ff434
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index c11050e..d6c3bc5 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -285,7 +285,7 @@
     }
 
     if (pAttributes == NULL) {
-        if (uint32_t(streamType) >= AUDIO_STREAM_CNT) {
+        if (uint32_t(streamType) >= AUDIO_STREAM_PUBLIC_CNT) {
             ALOGE("Invalid stream type %d", streamType);
             return BAD_VALUE;
         }