Mark libs as double_loadable

libs (libmedia_helper, libstagefright_omx_utils, libstagefright_xmlparser)
are VNDK and also used by LLNDK(libmediandk) which means these libs can be double-loaded.
(deps:
 - libmediandk -> libmedia -> libaudioclient -> libmedia_helper
 - libmediandk -> libmedia_jni -> libstagefright -> libstagefright_omx_utils
 - libmediandk -> libmedia_jni -> libstagefright -> libstagefright_xmlparser
)

Bug: 121280180
Test: m -j
Change-Id: Ibbf5dede1f503e86484f805b252d4ced779445cb
diff --git a/media/libmedia/Android.bp b/media/libmedia/Android.bp
index 9a1ac53..5853e4b 100644
--- a/media/libmedia/Android.bp
+++ b/media/libmedia/Android.bp
@@ -21,6 +21,7 @@
     vndk: {
         enabled: true,
     },
+    double_loadable: true,
     srcs: ["AudioParameter.cpp", "TypeConverter.cpp"],
     cflags: [
         "-Werror",
diff --git a/media/libstagefright/omx/Android.bp b/media/libstagefright/omx/Android.bp
index 362b7f5..4383004 100644
--- a/media/libstagefright/omx/Android.bp
+++ b/media/libstagefright/omx/Android.bp
@@ -87,6 +87,7 @@
     vndk: {
         enabled: true,
     },
+    double_loadable: true,
     srcs: ["OMXUtils.cpp"],
     export_include_dirs: [
         "include",
diff --git a/media/libstagefright/xmlparser/Android.bp b/media/libstagefright/xmlparser/Android.bp
index bebfb3b..819058c 100644
--- a/media/libstagefright/xmlparser/Android.bp
+++ b/media/libstagefright/xmlparser/Android.bp
@@ -10,6 +10,7 @@
     vndk: {
         enabled: true,
     },
+    double_loadable: true,
 
     srcs: [
         "MediaCodecsXmlParser.cpp",