Fixed <TextInput>.onContentSizeChange on Android

Summary:
Previously <TextInput>'s onContentSizeChange event fires very rearly, usually just once after initial layout. This diff fixed that.
I also considered to a bunch of another things to get the native notification, but I found that overriding `onTextChanged` is the most reliable, easy and effitient way to implement this.

I tried/considered:
 * onLayout (does not fire)
 * OnPreDrawListener (fires to often)
 * OnGlobalLayoutListener (does not fire)
 * OnLayoutChangeListener (does not fire)
 * isLayoutRequested (too hacky)

(I also fixed the <AutoExpandingTextInput> demo to illustrate the fix.)

And just heads up, we will remove `contentSize` info from `onChange` event very soon.

GH issue: facebook#11692

Reviewed By: achen1

Differential Revision: D5132589

fbshipit-source-id: e7edbd8dc5ae891a6f4a87b51d9450b8c6ce4a1e

RNTester/js/TextInputExample.android.js

@@ -49,6 +49,9 @@ class TextEventsExample extends React.Component {
           onChange={(event) => this.updateText(
             'onChange text: ' + event.nativeEvent.text
           )}
+          onContentSizeChange={(event) => this.updateText(
+            'onContentSizeChange size: ' + event.nativeEvent.contentSize
+          )}
           onEndEditing={(event) => this.updateText(
             'onEndEditing text: ' + event.nativeEvent.text
           )}
@@ -71,7 +74,6 @@ class AutoExpandingTextInput extends React.Component {
   constructor(props) {
     super(props);
     this.state = {
-      text: 'React Native enables you to build world-class application experiences on native platforms using a consistent developer experience based on JavaScript and React. The focus of React Native is on developer efficiency across all the platforms you care about — learn once, write anywhere. Facebook uses React Native in multiple production apps and will continue investing in React Native.',
       height: 0,
     };
   }
@@ -83,11 +85,7 @@ class AutoExpandingTextInput extends React.Component {
         onContentSizeChange={(event) => {
           this.setState({height: event.nativeEvent.contentSize.height});
         }}
-        onChangeText={(text) => {
-          this.setState({text});
-        }}
-        style={[styles.default, {height: Math.max(35, this.state.height)}]}
-        value={this.state.text}
+        style={[styles.default, {height: Math.min(200, Math.max(35, this.state.height))}]}
       />
     );
   }
@@ -619,6 +617,7 @@ exports.examples = [
         <View>
           <AutoExpandingTextInput
             placeholder="height increases with content"
+            defaultValue="React Native enables you to build world-class application experiences on native platforms using a consistent developer experience based on JavaScript and React. The focus of React Native is on developer efficiency across all the platforms you care about — learn once, write anywhere. Facebook uses React Native in multiple production apps and will continue investing in React Native."
             enablesReturnKeyAutomatically={true}
             returnKeyType="done"
           />

ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactEditText.java

@@ -629,6 +629,10 @@ public void onTextChanged(CharSequence s, int start, int before, int count) {
           listener.onTextChanged(s, start, before, count);
         }
       }
+
+      if (mContentSizeWatcher != null) {
+        mContentSizeWatcher.onLayout();
+      }
     }
 
     @Override