Convert AudioFlinger create* arguments to AIDL

This is a first step in AIDLizing IAudioFlinger, where we are
converting the in/out arguments from create{Track,Record} to stable
AIDL and add their respective conversion functions.

Bug: 160253486
Test: atest CtsMediaTestCases:Audio*
      Manual verification of common playback and recording scenarios.
Change-Id: Iabb28472aedd90efbba673fb68574876528228df
diff --git a/media/libshmem/Android.bp b/media/libshmem/Android.bp
index c8d2284..b549b5d 100644
--- a/media/libshmem/Android.bp
+++ b/media/libshmem/Android.bp
@@ -1,6 +1,9 @@
 aidl_interface {
     name: "shared-file-region-aidl",
     unstable: true,
+    host_supported: true,
+    vendor_available: true,
+    double_loadable: true,
     local_include_dir: "aidl",
     srcs: [
         "aidl/android/media/SharedFileRegion.aidl",