Migrate libmediandk to ndk_library.

Test: make native
Bug: http://b/30465923
Change-Id: Id62eac2d5cc518465445d87ce204fa918f0ddb68
diff --git a/Android.bp b/Android.bp
index 0990db6..0d7c30d 100644
--- a/Android.bp
+++ b/Android.bp
@@ -5,6 +5,13 @@
     srcs: ["include/camera/ndk/**/*.h"],
 }
 
+ndk_headers {
+    name: "libmediandk_headers",
+    from: "include/ndk/",
+    to: "media",
+    srcs: ["include/ndk/**/*.h"],
+}
+
 subdirs = [
     "camera/ndk",
     "media/libmedia",