Fixed a lot of dartanalyzer static analysis issues with the html lib.

sdk/lib/html/src/dartium_KeyEvent.dart

 /**
  * A custom KeyboardEvent that attempts to eliminate cross-browser
  * inconsistencies, and also provide both keyCode and charCode information
  * for all key events (when such information can be determined).
  *
  * This class is very much a work in progress, and we'd love to get information
  * on how we can make this class work with as many international keyboards as
  * possible. Bugs welcome!
  */
 class KeyEvent implements KeyboardEvent {
@@ skipping 86 matching lines @@
   void stopPropagation() => _parent.stopPropagation();
   void $dom_initUIEvent(String type, bool canBubble, bool cancelable,
       LocalWindow view, int detail) {
     throw new UnsupportedError("Cannot initialize a UI Event from a KeyEvent.");
   }
   void $dom_initEvent(String eventTypeArg, bool canBubbleArg,
       bool cancelableArg) {
     throw new UnsupportedError("Cannot initialize an Event from a KeyEvent.");
   }
   String get _shadowKeyIdentifier => _parent.$dom_keyIdentifier;
+
+  int get $dom_charCode => charCode;
+  int get $dom_keyCode => keyCode;
+  EventTarget get target => _parent.target;
+  String get $dom_keyIdentifier {
+    throw new UnsupportedError("keyIdentifier is unsupported.");
+  }
+  void $dom_initKeyboardEvent(String type, bool canBubble, bool cancelable,
+      LocalWindow view, String keyIdentifier, int keyLocation, bool ctrlKey,
+      bool altKey, bool shiftKey, bool metaKey,
+      bool altGraphKey) {
+    throw new UnsupportedError(
+        "Cannot initialize a KeyboardEvent from a KeyEvent.");
+  }
 }