Add libstagefright_foundation to native_shared_libs of apex

com.android.media.swcodec apex uses libstagefright_foundation.so
which has an apex variant that excludes links to libbinder.so.
On devices that doesn't use apex, the apex is a folder and these
libs by default will become symlinks to the lib in /system/libs.
This doesn't work for swcodec because the system variant links
to libbinder which is inaccessible from apex's namespace.

bug: 175592420
test: build wembley-userdebug;
- manually check that the out /apex/com.android.media.swcodec/libs
has the real libstagefright_foundation.so, not symlink
- 'readelf' the lib and shouldn't need libbinder.

Change-Id: Ic2dca3eb3395693346531d62bd3b6574d8c85d5f
diff --git a/apex/Android.bp b/apex/Android.bp
index f3e8a55..b314e5d 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -89,6 +89,9 @@
     binaries: [
         "mediaswcodec",
     ],
+    native_shared_libs: [
+        "libstagefright_foundation",
+    ],
     prebuilts: [
         "com.android.media.swcodec-mediaswcodec.rc",
         "com.android.media.swcodec-ld.config.txt",