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

sdk/lib/html/src/dart2js_KeyEvent.dart

Index: sdk/lib/html/src/dart2js_KeyEvent.dart
diff --git a/sdk/lib/html/src/dart2js_KeyEvent.dart b/sdk/lib/html/src/dart2js_KeyEvent.dart
index 9a07ea0c614f572adf579ee9b6c2db37bfdbda0f..83f73ff793405ff5b0f6e6ad1e77b243ebaa04f8 100644
--- a/sdk/lib/html/src/dart2js_KeyEvent.dart
+++ b/sdk/lib/html/src/dart2js_KeyEvent.dart
@@ -104,4 +104,18 @@ class KeyEvent implements KeyboardEvent {
     throw new UnsupportedError("Cannot initialize an Event from a KeyEvent.");
   }
   String get _shadowKeyIdentifier => JS('String', '#.keyIdentifier', _parent);
+
+  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.");
+  }
 }