RN: Delete TextInput.selectionState Prop

Summary:
Deletes the `selectionState` prop from `TextInput`.

It does not provide meaningful value over `onBlur`, `onFocus`, and `selectionState`.

Changelog:
[Breaking][TextInput] Removing `selectionState` prop, use `onBlur`, `onFocus`, and `onUpdate` instead.

Reviewed By: zackargyle, TheSavior

Differential Revision: D17879667

fbshipit-source-id: 03a4e239406932adad898d6d2a092e3bc2e6b064

Libraries/Components/TextInput/TextInput.js

@@ -10,7 +10,6 @@
 'use strict';
 
 const DeprecatedTextInputPropTypes = require('../../DeprecatedPropTypes/DeprecatedTextInputPropTypes');
-const DocumentSelectionState = require('../../vendor/document/selection/DocumentSelectionState');
 const NativeMethodsMixin = require('../../Renderer/shims/NativeMethodsMixin');
 const Platform = require('../../Utilities/Platform');
 const React = require('react');
@@ -221,23 +220,6 @@ type IOSProps = $ReadOnly<{|
    */
   enablesReturnKeyAutomatically?: ?boolean,
 
-  /**
-   * An instance of `DocumentSelectionState`, this is some state that is responsible for
-   * maintaining selection information for a document.
-   *
-   * Some functionality that can be performed with this instance is:
-   *
-   * - `blur()`
-   * - `focus()`
-   * - `update()`
-   *
-   * > You can reference `DocumentSelectionState` in
-   * > [`vendor/document/selection/DocumentSelectionState.js`](https://github.com/facebook/react-native/blob/master/Libraries/vendor/document/selection/DocumentSelectionState.js)
-   *
-   * @platform ios
-   */
-  selectionState?: ?DocumentSelectionState,
-
   /**
    * When the clear button should appear on the right side of the text view.
    * This property is supported only for single-line TextInput component.
@@ -1115,10 +1097,6 @@ const TextInput = createReactClass({
     if (this.props.onFocus) {
       this.props.onFocus(event);
     }
-
-    if (this.props.selectionState) {
-      this.props.selectionState.focus();
-    }
   },
 
   _onPress: function(event: PressEvent) {
@@ -1161,7 +1139,7 @@ const TextInput = createReactClass({
 
     this._lastNativeSelection = event.nativeEvent.selection;
 
-    if (this.props.selection || this.props.selectionState) {
+    if (this.props.selection) {
       this.forceUpdate();
     }
   },
@@ -1198,10 +1176,6 @@ const TextInput = createReactClass({
     ) {
       this._inputRef.setNativeProps(nativeProps);
     }
-
-    if (this.props.selectionState && selection) {
-      this.props.selectionState.update(selection.start, selection.end);
-    }
   },
 
   _onBlur: function(event: BlurEvent) {
@@ -1211,10 +1185,6 @@ const TextInput = createReactClass({
     if (this.props.onBlur) {
       this.props.onBlur(event);
     }
-
-    if (this.props.selectionState) {
-      this.props.selectionState.blur();
-    }
   },
 
   _onTextInput: function(event: TextInputEvent) {