Log and skip init of synthetic keyboard events for IE11

We don't have a solution synthetic keyboard events in IE11
so this patch changes it to skip the initialization and log
the issue instead of throwing an exception.

Bug: issue 8463
Change-Id: I8230e542c7a6ec74418d62f6c4b3aadf41de59e1
Review-Link: https://gwt-review.googlesource.com/#/c/10202/
(cherry picked from commit d25051f64d60083d5e38f052f71ab49f96776963)

user/src/com/google/gwt/dom/client/DOMImplMozilla.java

diff --git a/user/src/com/google/gwt/dom/client/DOMImplMozilla.java b/user/src/com/google/gwt/dom/client/DOMImplMozilla.java
index ab41f8d..d246e85 100644
--- a/user/src/com/google/gwt/dom/client/DOMImplMozilla.java
+++ b/user/src/com/google/gwt/dom/client/DOMImplMozilla.java
@@ -224,9 +224,17 @@
   private native NativeEvent createKeyEventImpl(Document doc, String type,
       boolean canBubble, boolean cancelable, boolean ctrlKey, boolean altKey,
       boolean shiftKey, boolean metaKey, int keyCode, int charCode) /*-{
-    var evt = doc.createEvent('KeyEvents');
-    evt.initKeyEvent(type, canBubble, cancelable, null, ctrlKey, altKey,
-      shiftKey, metaKey, keyCode, charCode);
+    var evt = doc.createEvent('KeyboardEvent');
+    if (evt.initKeyEvent) {
+      // Gecko
+      evt.initKeyEvent(type, canBubble, cancelable, null, ctrlKey, altKey,
+        shiftKey, metaKey, keyCode, charCode);
+    } else {
+      // This happens to be IE11+ as of today
+      if ($wnd.console) {
+        $wnd.console.error("Synthetic keyboard events are not supported in this browser");
+      }
+    }
     return evt;
   }-*/;