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/react/bridge/WritableNativeMap.java

@@ -0,0 +1,68 @@
+/**
+ * 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.react.bridge;
+
+import com.facebook.infer.annotation.Assertions;
+import com.facebook.proguard.annotations.DoNotStrip;
+import com.facebook.soloader.SoLoader;
+
+/**
+ * Implementation of a write-only map stored in native memory. Use
+ * {@link Arguments#createMap()} if you need to stub out creating this class in a test.
+ * TODO(5815532): Check if consumed on read
+ */
+@DoNotStrip
+public class WritableNativeMap extends ReadableNativeMap implements WritableMap {
+
+  static {
+    SoLoader.loadLibrary(ReactBridge.REACT_NATIVE_LIB);
+  }
+
+  @Override
+  public native void putBoolean(String key, boolean value);
+  @Override
+  public native void putDouble(String key, double value);
+  @Override
+  public native void putString(String key, String value);
+  @Override
+  public native void putNull(String key);
+
+  @Override
+  public void putInt(String key, int value) {
+    putDouble(key, value);
+  }
+
+  // Note: this consumes the map so do not reuse it.
+  @Override
+  public void putMap(String key, WritableMap value) {
+    Assertions.assertCondition(
+        value == null || value instanceof WritableNativeMap, "Illegal type provided");
+    putNativeMap(key, (WritableNativeMap) value);
+  }
+
+  // Note: this consumes the map so do not reuse it.
+  @Override
+  public void putArray(String key, WritableArray value) {
+    Assertions.assertCondition(
+        value == null || value instanceof WritableNativeArray, "Illegal type provided");
+    putNativeArray(key, (WritableNativeArray) value);
+  }
+
+  // Note: this **DOES NOT** consume the source map
+  @Override
+  public void merge(ReadableMap source) {
+    Assertions.assertCondition(source instanceof ReadableNativeMap, "Illegal type provided");
+    mergeNativeMap((ReadableNativeMap) source);
+  }
+
+  private native void putNativeMap(String key, WritableNativeMap value);
+  private native void putNativeArray(String key, WritableNativeArray value);
+  private native void mergeNativeMap(ReadableNativeMap source);
+}