Split YogaConfig into interface and actual implementation

Summary:
Split YogaConfig into the same way YogaNode is split today.

Into an abstract class defining the interface, and actual JNI implementation

Reviewed By: SidharthGuglani

Differential Revision: D17266404

fbshipit-source-id: 3d5d6aa65c55cfa61d47c662d140cdce6dcb0ea1

java/com/facebook/yoga/YogaConfigJNIFinalizer.java

@@ -0,0 +1,30 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+package com.facebook.yoga;
+
+public class YogaConfigJNIFinalizer extends YogaConfigJNIBase {
+  public YogaConfigJNIFinalizer() {
+    super();
+  }
+
+  @Override
+  protected void finalize() throws Throwable {
+    try {
+      freeNatives();
+    } finally {
+      super.finalize();
+    }
+   }
+
+  public void freeNatives() {
+    if (mNativePointer != 0) {
+      long nativePointer = mNativePointer;
+      mNativePointer = 0;
+      YogaNative.jni_YGConfigFree(nativePointer);
+    }
+  }
+}