Use art_defaults in libnative*, for consistency.

Also change to //art:__submodules__ for consistent internal visibility, and
some TODO comment corrections.

Test: m WITH_TIDY=1
Test: build & boot
Test: atest art/libnativeloader/test (no new errors, but existing ones on arm64 - b/142896688)
Test: (atest art/libnativebridge/tests doesn't work at all, but that's not new - b/142897320)
Bug: 137364733
Bug: 133140750
Change-Id: If9ddb5a597eea3606342c3625dcdb3bcf5d19041
diff --git a/libnativeloader/library_namespaces.cpp b/libnativeloader/library_namespaces.cpp
index 7246b97..ef97959 100644
--- a/libnativeloader/library_namespaces.cpp
+++ b/libnativeloader/library_namespaces.cpp
@@ -33,8 +33,6 @@
 #include "public_libraries.h"
 #include "utils.h"
 
-using android::base::Error;
-
 namespace android::nativeloader {
 
 namespace {
@@ -71,11 +69,11 @@
 const std::regex kProductDexPathRegex("(^|:)(/system)?/product/");
 
 // Define origin of APK if it is from vendor partition or product partition
-typedef enum {
+using ApkOrigin = enum {
   APK_ORIGIN_DEFAULT = 0,
   APK_ORIGIN_VENDOR = 1,
   APK_ORIGIN_PRODUCT = 2,
-} ApkOrigin;
+};
 
 jobject GetParentClassLoader(JNIEnv* env, jobject class_loader) {
   jclass class_loader_class = env->FindClass("java/lang/ClassLoader");