Release React Native for Android

This is an early release and there are several things that are known
not to work if you're porting your iOS app to Android.

See the Known Issues guide on the website.

We will work with the community to reach platform parity with iOS.

ReactAndroid/src/main/java/com/facebook/jni/Countable.java

@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+package com.facebook.jni;
+
+import com.facebook.proguard.annotations.DoNotStrip;
+
+/**
+ * A Java Object that has native memory allocated corresponding to this instance.
+ *
+ * NB: THREAD SAFETY (this comment also exists at Countable.cpp)
+ *
+ * {@link #dispose} deletes the corresponding native object on whatever thread the method is called
+ * on. In the common case when this is called by Countable#finalize(), this will be called on the
+ * system finalizer thread. If you manually call dispose on the Java object, the native object
+ * will be deleted synchronously on that thread.
+ */
+@DoNotStrip
+public class Countable {
+  // Private C++ instance
+  @DoNotStrip
+  private long mInstance = 0;
+
+  public Countable() {
+    Prerequisites.ensure();
+  }
+
+  public native void dispose();
+
+  protected void finalize() throws Throwable {
+    dispose();
+    super.finalize();
+  }
+}