Fixed controlled component on iOS and remove unnecessary code

Summary:
Closes #4290

`mostRecentEventCount` was always being set after `text` on iOS, so let's be really explicit about the order here as we were doing on Android: always call `setNativeProps` providing the `mostRecentEventCount` before we call `onChange` or `onChangeText`.

I also ripped out storing `mostRecentEventCount` in the state, which isn't necessary since we're always doing it through `setNativeProps`.
Closes https://github.com/facebook/react-native/pull/4588

Reviewed By: svcscm

Differential Revision: D2754565

Pulled By: nicklockwood

fb-gh-sync-id: a1401f39b4e19248095517c2a3503cd2af59fa47

Examples/UIExplorer/TextInputExample.ios.js

@@ -125,6 +125,27 @@ class RewriteExample extends React.Component {
   }
 }
 
+class RewriteExampleInvalidCharacters extends React.Component {
+  constructor(props) {
+    super(props);
+    this.state = {text: ''};
+  }
+  render() {
+    return (
+      <View style={styles.rewriteContainer}>
+        <TextInput
+          multiline={false}
+          onChangeText={(text) => {
+            this.setState({text: text.replace(/\s/g, '')});
+          }}
+          style={styles.default}
+          value={this.state.text}
+        />
+      </View>
+    );
+  }
+}
+
 class TokenizedTextExample extends React.Component {
   constructor(props) {
     super(props);
@@ -313,6 +334,12 @@ exports.examples = [
       return <RewriteExample />;
     }
   },
+  {
+    title: "Live Re-Write (no spaces allowed)",
+    render: function() {
+      return <RewriteExampleInvalidCharacters />;
+    }
+  },
   {
     title: 'Auto-capitalize',
     render: function() {

Libraries/Components/TextInput/TextInput.js

@@ -329,12 +329,6 @@ var TextInput = React.createClass({
       React.findNodeHandle(this.refs.input);
   },
 
-  getInitialState: function() {
-    return {
-      mostRecentEventCount: 0,
-    };
-  },
-
   contextTypes: {
     onFocusRequested: React.PropTypes.func,
     focusEmitter: React.PropTypes.instanceOf(EventEmitter),
@@ -431,7 +425,6 @@ var TextInput = React.createClass({
           onSelectionChange={onSelectionChange}
           onSelectionChangeShouldSetResponder={emptyFunction.thatReturnsTrue}
           text={this._getText()}
-          mostRecentEventCount={this.state.mostRecentEventCount}
         />;
     } else {
       for (var propKey in notMultiline) {
@@ -460,7 +453,6 @@ var TextInput = React.createClass({
           ref="input"
           {...props}
           children={children}
-          mostRecentEventCount={this.state.mostRecentEventCount}
           onFocus={this._onFocus}
           onBlur={this._onBlur}
           onChange={this._onChange}
@@ -506,7 +498,7 @@ var TextInput = React.createClass({
         textAlign={textAlign}
         textAlignVertical={textAlignVertical}
         keyboardType={this.props.keyboardType}
-        mostRecentEventCount={this.state.mostRecentEventCount}
+        mostRecentEventCount={0}
         multiline={this.props.multiline}
         numberOfLines={this.props.numberOfLines}
         maxLength={this.props.maxLength}
@@ -548,29 +540,24 @@ var TextInput = React.createClass({
   },
 
   _onChange: function(event: Event) {
-    if (Platform.OS === 'android') {
-      // Android expects the event count to be updated as soon as possible.
-      this.refs.input.setNativeProps({
-        mostRecentEventCount: event.nativeEvent.eventCount,
-      });
-    }
+    // Make sure to fire the mostRecentEventCount first so it is already set on
+    // native when the text value is set.
+    this.refs.input.setNativeProps({
+      mostRecentEventCount: event.nativeEvent.eventCount,
+    });
+
     var text = event.nativeEvent.text;
-    var eventCount = event.nativeEvent.eventCount;
     this.props.onChange && this.props.onChange(event);
     this.props.onChangeText && this.props.onChangeText(text);
-    this.setState({mostRecentEventCount: eventCount}, () => {
-      // NOTE: this doesn't seem to be needed on iOS - keeping for now in case it's required on Android
-      if (Platform.OS === 'android') {
-        // This is a controlled component, so make sure to force the native value
-        // to match.  Most usage shouldn't need this, but if it does this will be
-        // more correct but might flicker a bit and/or cause the cursor to jump.
-        if (text !== this.props.value && typeof this.props.value === 'string') {
-          this.refs.input.setNativeProps({
-            text: this.props.value,
-          });
-        }
-      }
-    });
+
+    // This is necessary in case native updates the text and JS decides
+    // that the update should be ignored and we should stick with the value
+    // that we have in JS.
+    if (text !== this.props.value && typeof this.props.value === 'string') {
+      this.refs.input.setNativeProps({
+        text: this.props.value,
+      });
+    }
   },
 
   _onBlur: function(event: Event) {