nativeloader: Export FindNamespaceByClassLoader

Bug: http://b/27189432
Change-Id: Ib80dcce949276ee620f601c47b20f783708e8e85
(cherry picked from commit 0cd10d83e4e14300d03a60f28547b90d0c805579)
diff --git a/libnativeloader/native_loader.cpp b/libnativeloader/native_loader.cpp
index 468bfc6..8b8dee3 100644
--- a/libnativeloader/native_loader.cpp
+++ b/libnativeloader/native_loader.cpp
@@ -105,6 +105,14 @@
     return ns;
   }
 
+  android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
+    auto it = std::find_if(namespaces_.begin(), namespaces_.end(),
+                [&](const std::pair<jweak, android_namespace_t*>& value) {
+                  return env->IsSameObject(value.first, class_loader);
+                });
+    return it != namespaces_.end() ? it->second : nullptr;
+  }
+
  private:
   void PreloadPublicLibraries() {
     // android_init_namespaces() expects all the public libraries
@@ -132,14 +140,6 @@
     return initialized_;
   }
 
-  android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
-    auto it = std::find_if(namespaces_.begin(), namespaces_.end(),
-                [&](const std::pair<jweak, android_namespace_t*>& value) {
-                  return env->IsSameObject(value.first, class_loader);
-                });
-    return it != namespaces_.end() ? it->second : nullptr;
-  }
-
   bool initialized_;
   std::mutex mutex_;
   std::vector<std::pair<jweak, android_namespace_t*>> namespaces_;
@@ -179,4 +179,10 @@
 #endif
 }
 
+#if defined(__ANDROID__)
+android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
+  return g_namespaces->FindNamespaceByClassLoader(env, class_loader);
+}
+#endif
+
 }; //  android namespace