Automatically init native memory when allocating java wrapper

Summary: Don't require calling init() to used an allocated object. This makes more sense and is more in line with how jni in java is generally managed.

Reviewed By: lucasr

Differential Revision: D3992802

fbshipit-source-id: 06d65821f1802ed8f2b2db651cef69f6851803f2

java/com/facebook/csslayout/CSSNode.java

@@ -35,6 +35,10 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
   private long mNativePointer;
   private Object mData;
 
+  public CSSNode() {
+    init();
+  }
+
   private void assertNativeInstance() {
     if (mNativePointer == 0) {
       throw new IllegalStateException("Null native pointer");