Implements blurOnSubmit

Summary: The default value (to retain current behavior) is set to `true`. Setting the value to `false` will prevent the textField from blurring but still fire the `onSubmitEditing` callback. However, the `onEndEditing` callback will not be fired.

Addresses issue: https://github.com/facebook/react-native/issues/2129
Closes https://github.com/facebook/react-native/pull/2149

Reviewed By: svcscm

Differential Revision: D2619822

Pulled By: nicklockwood

fb-gh-sync-id: 9a61152892f4afb5c6c53e7b38dffae13bc7e13f

Libraries/Components/TextInput/TextInput.js

@@ -47,6 +47,10 @@ if (Platform.OS === 'android') {
   var RCTTextField = requireNativeComponent('RCTTextField', null);
 }
 
+type DefaultProps = {
+  blurOnSubmit: boolean;
+};
+
 type Event = Object;
 
 /**
@@ -283,6 +287,12 @@ var TextInput = React.createClass({
      * @platform ios
      */
     selectTextOnFocus: PropTypes.bool,
+    /**
+     * If true, the text field will blur when submitted.
+     * The default value is true.
+     * @platform ios
+     */
+    blurOnSubmit: PropTypes.bool,
     /**
      * Styles
      */
@@ -298,6 +308,12 @@ var TextInput = React.createClass({
     underlineColorAndroid: PropTypes.string,
   },
 
+  getDefaultProps: function(): DefaultProps {
+    return {
+      blurOnSubmit: true,
+    };
+  },
+
   /**
    * `NativeMethodsMixin` will look for this when invoking `setNativeProps`. We
    * make `this` look like an actual native component class.