chore(syntheticEvent): remove IE8 code (#11178)

* chore(syntheticEvent): remove IE8 code

Since IE8 has been deprecated for a while, I thought it might be useful to remove some IE8-only code

If this is not something you want to focus on yet, or is too much work to test, feel free to close this PR

* Update SyntheticUIEvent.js

* Update SyntheticUIEvent.js

* remove unused require

* completely remove UIEvent

* augment with noop

everything breaks otherwise

* comment back

* spacing

src/renderers/dom/shared/syntheticEvents/SyntheticUIEvent.js

@@ -11,35 +11,13 @@
 
 var SyntheticEvent = require('SyntheticEvent');
 
-var getEventTarget = require('getEventTarget');
-
 /**
  * @interface UIEvent
  * @see http://www.w3.org/TR/DOM-Level-3-Events/
  */
 var UIEventInterface = {
-  view: function(event) {
-    if (event.view) {
-      return event.view;
-    }
-
-    var target = getEventTarget(event);
-    if (target.window === target) {
-      // target is a window object
-      return target;
-    }
-
-    var doc = target.ownerDocument;
-    // TODO: Figure out why `ownerDocument` is sometimes undefined in IE8.
-    if (doc) {
-      return doc.defaultView || doc.parentWindow;
-    } else {
-      return window;
-    }
-  },
-  detail: function(event) {
-    return event.detail || 0;
-  },
+  view: null,
+  detail: null,
 };
 
 /**