Add constructors to all the event classes.

client/html/src/CompositionEventWrappingImplementation.dart

Index: client/html/src/CompositionEventWrappingImplementation.dart
diff --git a/client/html/generated/src/wrapping/_CompositionEventWrappingImplementation.dart b/client/html/src/CompositionEventWrappingImplementation.dart
similarity index 51%
rename from client/html/generated/src/wrapping/_CompositionEventWrappingImplementation.dart
rename to client/html/src/CompositionEventWrappingImplementation.dart
index 6a8e4ae0540e677a43be8041e7f215ee6c38100e..765f02238b1097e0a2283f4b9216ce50c41a70e6 100644
--- a/client/html/generated/src/wrapping/_CompositionEventWrappingImplementation.dart
+++ b/client/html/src/CompositionEventWrappingImplementation.dart
@@ -2,15 +2,16 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// WARNING: Do not edit - generated code.
-
 class CompositionEventWrappingImplementation extends UIEventWrappingImplementation implements CompositionEvent {
-  CompositionEventWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
-
-  String get data() { return _ptr.data; }
+  CompositionEventWrappingImplementation._wrap(ptr) : super._wrap(ptr);
 
-  void initCompositionEvent(String typeArg, bool canBubbleArg, bool cancelableArg, Window viewArg, String dataArg) {
-    _ptr.initCompositionEvent(typeArg, canBubbleArg, cancelableArg, LevelDom.unwrap(viewArg), dataArg);
-    return;
+  factory CompositionEventWrappingImplementation(String type, Window view,
+      String data, [bool canBubble = true, bool cancelable = true]) {
+    final e = dom.document.createEvent("CompositionEvent");
+    e.initCompositionEvent(type, canBubble, cancelable, LevelDom.unwrap(view),
+        data);
+    return LevelDom.wrapCompositionEvent(e);
   }
+
+  String get data() => _ptr.data;
 }