[fixed] Split toggleAriaHidden internal method to two methods

This change makes things much more reliable overall by preventing
some cross-browser concerns where the method ended up being
triggered more than once causing it to reverse from the expected
behavior

lib/components/TrayPortal.js

@@ -105,12 +105,12 @@ export default React.createClass({
     this.refs.content.focus();
   },
 
-  toggleAriaHidden(element) {
-    if (!element.getAttribute('aria-hidden')) {
-      element.setAttribute('aria-hidden', true);
-    } else {
-      element.removeAttribute('aria-hidden');
-    }
+  applyAriaHidden(element) {
+    element.setAttribute('aria-hidden', true);
+  },
+
+  removeAriaHidden(element) {
+    element.removeAttribute('aria-hidden');
   },
 
   handleOverlayClick(e) {
@@ -148,7 +148,7 @@ export default React.createClass({
         this.props.onOpen();
       }
       if (this.props.getAriaHideElement) {
-        this.toggleAriaHidden(this.props.getAriaHideElement());
+        this.applyAriaHidden(this.props.getAriaHideElement());
       }
       this.setState({afterOpen: true});
     });
@@ -161,7 +161,7 @@ export default React.createClass({
       this.closeWithoutTimeout();
     }
     if (this.props.getAriaHideElement) {
-      this.toggleAriaHidden(this.props.getAriaHideElement());
+      this.removeAriaHidden(this.props.getAriaHideElement());
     }
   },