Enable flow in react-native-implementation

Summary:
I noticed I didn't get type defs anymore for react-native. Looks like it is broken since we removed the .flow file in 3e153b2a5b. To fix it we can now enable flow in react-native-implementation since it now supports properties.

**Test plan**
Tested that I get type hints when using imports from react-native in a project.
Closes https://github.com/facebook/react-native/pull/12917

Differential Revision: D4704753

Pulled By: ericvicenti

fbshipit-source-id: cf882588d7f371931de8d7861a1a6d50f6c425dc

Examples/UIExplorer/js/FlatListExample.js

@@ -198,7 +198,7 @@ class FlatListExample extends React.PureComponent {
     this._listRef.getNode().recordInteraction();
     pressItem(this, key);
   };
-  _listRef: FlatList<*>;
+  _listRef: AnimatedFlatList;
 }
 
 

Examples/UIExplorer/js/NativeAnimationsExample.js

@@ -49,7 +49,7 @@ class Tester extends React.Component {
       this.current && this.props.reverseConfig ? this.props.reverseConfig : this.props.config
     );
     this.current = this.current ? 0 : 1;
-    const config = {
+    const config: Object = {
       ...animConfig,
       toValue: this.current,
     };

Examples/UIExplorer/js/ScrollViewExample.js

@@ -71,7 +71,7 @@ exports.examples = [
   description: 'You can display <ScrollView>\'s child components horizontally rather than vertically',
   render: function() {
 
-    function renderScrollView(title: string, addtionalStyles: StyleSheet) {
+    function renderScrollView(title: string, addtionalStyles: typeof StyleSheet) {
       var _scrollView: ScrollView;
       return (
         <View style={addtionalStyles}>

Libraries/Components/Picker/Picker.js

@@ -33,6 +33,44 @@ var pickerStyleType = StyleSheetPropType({
 var MODE_DIALOG = 'dialog';
 var MODE_DROPDOWN = 'dropdown';
 
+/**
+ * Individual selectable item in a Picker.
+ */
+class PickerItem extends React.Component {
+ props: {
+  label: string,
+  value?: any,
+  color?: ColorPropType,
+  testID?: string,
+ };
+
+ static propTypes = {
+   /**
+    * Text to display for this item.
+    */
+   label: React.PropTypes.string.isRequired,
+   /**
+    * The value to be passed to picker's `onValueChange` callback when
+    * this item is selected. Can be a string or an integer.
+    */
+   value: React.PropTypes.any,
+   /**
+    * Color of this item's text.
+    * @platform android
+    */
+   color: ColorPropType,
+   /**
+    * Used to locate the item in end-to-end tests.
+    */
+   testID: React.PropTypes.string,
+ };
+
+ render() {
+   // The items are not rendered directly
+   throw null;
+ }
+}
+
 /**
  * Renders the native picker component on iOS and Android. Example:
  *
@@ -65,6 +103,8 @@ class Picker extends React.Component {
   */
  static MODE_DROPDOWN = MODE_DROPDOWN;
 
+ static Item = PickerItem;
+
  static defaultProps = {
    mode: MODE_DIALOG,
  };
@@ -127,43 +167,4 @@ class Picker extends React.Component {
  }
 }
 
-/**
- * Individual selectable item in a Picker.
- */
-// $FlowFixMe found when converting React.createClass to ES6
-Picker.Item = class extends React.Component {
- props: {
-  label: string,
-  value?: any,
-  color?: ColorPropType,
-  testID?: string,
- };
-
- static propTypes = {
-   /**
-    * Text to display for this item.
-    */
-   label: React.PropTypes.string.isRequired,
-   /**
-    * The value to be passed to picker's `onValueChange` callback when
-    * this item is selected. Can be a string or an integer.
-    */
-   value: React.PropTypes.any,
-   /**
-    * Color of this item's text.
-    * @platform android
-    */
-   color: ColorPropType,
-   /**
-    * Used to locate the item in end-to-end tests.
-    */
-   testID: React.PropTypes.string,
- };
-
- render() {
-   // The items are not rendered directly
-   throw null;
- }
-};
-
 module.exports = Picker;

Libraries/Experimental/SwipeableRow/SwipeableListView.js

@@ -18,6 +18,11 @@ const SwipeableRow = require('SwipeableRow');
 
 const {PropTypes} = React;
 
+type DefaultProps = {
+  bounceFirstRowOnMount: boolean,
+  renderQuickActions: Function,
+};
+
 type Props = {
   bounceFirstRowOnMount: boolean,
   dataSource: SwipeableListViewDataSource,
@@ -49,7 +54,7 @@ type State = {
  * - It can bounce the 1st row of the list so users know it's swipeable
  * - More to come
  */
-class SwipeableListView extends React.Component {
+class SwipeableListView extends React.Component<DefaultProps, Props, State> {
   props: Props;
   state: State;
 

Libraries/Image/Image.android.js

@@ -194,7 +194,7 @@ var Image = React.createClass({
     getSize(
       url: string,
       success: (width: number, height: number) => void,
-      failure: (error: any) => void,
+      failure?: (error: any) => void,
     ) {
       return ImageLoader.getSize(url)
         .then(function(sizes) {

Libraries/Image/Image.ios.js

@@ -304,7 +304,7 @@ const Image = React.createClass({
     getSize: function(
       uri: string,
       success: (width: number, height: number) => void,
-      failure: (error: any) => void,
+      failure?: (error: any) => void,
     ) {
       ImageViewManager.getSize(uri, success, failure || function() {
         console.warn('Failed to get size for image: ' + uri);

Libraries/react-native/react-native-implementation.js

@@ -7,24 +7,11 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @providesModule react-native-implementation
- * @noflow - get/set properties not yet supported by flow. also `...require(x)` is broken #6560135
+ * @flow
  */
 'use strict';
 
 const invariant = require('fbjs/lib/invariant');
-const warning = require('fbjs/lib/warning');
-
-if (__DEV__) {
-  var warningDedupe = {};
-  var addonWarn = function(prevName, newPackageName) {
-    warning(
-      warningDedupe[prevName],
-      'React.addons.' + prevName + ' is deprecated. Please import the "' +
-      newPackageName + '" package instead.'
-    );
-    warningDedupe[prevName] = true;
-  };
-}
 
 // Export React, plus some native additions.
 const ReactNative = {
@@ -118,6 +105,7 @@ const ReactNative = {
   get Platform() { return require('Platform'); },
   get processColor() { return require('processColor'); },
   get requireNativeComponent() { return require('requireNativeComponent'); },
+  get takeSnapshot() { return require('takeSnapshot'); },
 
   // Prop Types
   get ColorPropType() { return require('ColorPropType'); },
@@ -133,7 +121,6 @@ const ReactNative = {
       'and imported from `react-native-deprecated-custom-components` instead of `react-native`. ' +
       'Learn about alternative navigation solutions at http://facebook.github.io/react-native/docs/navigation.html'
     );
-    return null;
   },
 };