Update to not use _mountImage

See facebook/react#852.

Author: sophiebits

src/ReactART.js

@@ -81,7 +81,7 @@ var ContainerMixin = merge(ReactMultiChild.Mixin, {
    * @protected
    */
   moveChild: function(child, toIndex) {
-    var childNode = child._mountImage;
+    var childNode = this._childNodes[child._rootNodeID];
     var mostRecentlyPlacedChild = this._mostRecentlyPlacedChild;
     if (mostRecentlyPlacedChild == null) {
       // I'm supposed to be first.
@@ -109,10 +109,15 @@ var ContainerMixin = merge(ReactMultiChild.Mixin, {
    * Creates a child component.
    *
    * @param {ReactComponent} child Component to create.
+   * @param {object} childNode ART node to insert.
    * @protected
    */
-  createChild: function(child) {
-    var childNode = child._mountImage;
+  createChild: function(child, childNode) {
+    if (this._childNodes == null) {
+      this._childNodes = {};
+    }
+    this._childNodes[child._rootNodeID] = childNode;
+
     var mostRecentlyPlacedChild = this._mostRecentlyPlacedChild;
     if (mostRecentlyPlacedChild == null) {
       // I'm supposed to be first.
@@ -139,7 +144,9 @@ var ContainerMixin = merge(ReactMultiChild.Mixin, {
    * @protected
    */
   removeChild: function(child) {
-    child._mountImage.eject();
+    var childNode = this._childNodes[child._rootNodeID];
+    childNode.eject();
+    delete this._childNodes[child._rootNodeID];
   },
 
   /**