Updating KeyboardEvent constructor to use named parameters.

tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate

Index: tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
diff --git a/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate b/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
index 15daf48959c748ec985f4318501552c17328a6e4..7c4b25ae14902ac86dc93f3945f52028214a035a 100644
--- a/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
+++ b/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
@@ -5,11 +5,14 @@
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
-  factory $CLASSNAME(String type, Window view,
-      [bool canBubble = true, bool cancelable = true,
-      String keyIdentifier = "", int keyLocation = 1, bool ctrlKey = false,
-      bool altKey = false, bool shiftKey = false, bool metaKey = false,
-      bool altGraphKey = false]) {
+  factory $CLASSNAME(String type,
+      {Window view, bool canBubble: true, bool cancelable: true,
+      String keyIdentifier: "", int keyLocation: 1, bool ctrlKey: false,
+      bool altKey: false, bool shiftKey: false, bool metaKey: false,
+      bool altGraphKey: false}) {
+    if (view == null) {
+      view = window;
+    }
     final e = document.$dom_createEvent("KeyboardEvent");
     e.$dom_initKeyboardEvent(type, canBubble, cancelable, view, keyIdentifier,
         keyLocation, ctrlKey, altKey, shiftKey, metaKey, altGraphKey);