Remove DOM mutation listeners

Mutation listeners are known to be slow. Rough benchmarks show text
changes are now 50% faster.

src/core/ReactEventEmitter.js

@@ -257,11 +257,6 @@ var ReactEventEmitter = merge(ReactEventEmitterMixin, {
       'selectionchange',
       mountAt
     );
-    trapBubbledEvent(
-      topLevelTypes.topDOMCharacterDataModified,
-      'DOMCharacterDataModified',
-      mountAt
-    );
 
     trapBubbledEvent(
       topLevelTypes.topCompositionEnd,

src/event/EventConstants.js

@@ -34,7 +34,6 @@ var topLevelTypes = keyMirror({
   topCompositionUpdate: null,
   topCopy: null,
   topCut: null,
-  topDOMCharacterDataModified: null,
   topDoubleClick: null,
   topDrag: null,
   topDragEnd: null,

src/event/synthetic/SyntheticMutationEvent.js

@@ -1,48 +0,0 @@
-/**
- * Copyright 2013 Facebook, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- * @providesModule SyntheticMutationEvent
- * @typechecks static-only
- */
-
-"use strict";
-
-var SyntheticEvent = require('SyntheticEvent');
-
-/**
- * @interface MutationEvent
- * @see http://www.w3.org/TR/DOM-Level-3-Events/
- */
-var MutationEventInterface = {
-  relatedNode: null,
-  prevValue: null,
-  newValue: null,
-  attrName: null,
-  attrChange: null
-};
-
-/**
- * @param {object} dispatchConfig Configuration used to dispatch this event.
- * @param {string} dispatchMarker Marker identifying the event target.
- * @param {object} nativeEvent Native browser event.
- * @extends {SyntheticEvent}
- */
-function SyntheticMutationEvent(dispatchConfig, dispatchMarker, nativeEvent) {
-  SyntheticEvent.call(this, dispatchConfig, dispatchMarker, nativeEvent);
-}
-
-SyntheticEvent.augmentClass(SyntheticMutationEvent, MutationEventInterface);
-
-module.exports = SyntheticMutationEvent;

src/eventPlugins/SimpleEventPlugin.js

@@ -25,7 +25,6 @@ var SyntheticEvent = require('SyntheticEvent');
 var SyntheticFocusEvent = require('SyntheticFocusEvent');
 var SyntheticKeyboardEvent = require('SyntheticKeyboardEvent');
 var SyntheticMouseEvent = require('SyntheticMouseEvent');
-var SyntheticMutationEvent = require('SyntheticMutationEvent');
 var SyntheticTouchEvent = require('SyntheticTouchEvent');
 var SyntheticUIEvent = require('SyntheticUIEvent');
 var SyntheticWheelEvent = require('SyntheticWheelEvent');
@@ -114,12 +113,6 @@ var eventTypes = {
       captured: keyOf({onDropCapture: true})
     }
   },
-  DOMCharacterDataModified: {
-    phasedRegistrationNames: {
-      bubbled: keyOf({onDOMCharacterDataModified: true}),
-      captured: keyOf({onDOMCharacterDataModifiedCapture: true})
-    }
-  },
   focus: {
     phasedRegistrationNames: {
       bubbled: keyOf({onFocus: true}),
@@ -226,7 +219,6 @@ var topLevelEventsToDispatchConfig = {
   topCopy:        eventTypes.copy,
   topCut:         eventTypes.cut,
   topDoubleClick: eventTypes.doubleClick,
-  topDOMCharacterDataModified: eventTypes.DOMCharacterDataModified,
   topDrag:        eventTypes.drag,
   topDragEnd:     eventTypes.dragEnd,
   topDragEnter:   eventTypes.dragEnter,
@@ -328,9 +320,6 @@ var SimpleEventPlugin = {
       case topLevelTypes.topMouseUp:
         EventConstructor = SyntheticMouseEvent;
         break;
-      case topLevelTypes.topDOMCharacterDataModified:
-        EventConstructor = SyntheticMutationEvent;
-        break;
       case topLevelTypes.topTouchCancel:
       case topLevelTypes.topTouchEnd:
       case topLevelTypes.topTouchMove: