Add constructors to all the event classes.

client/html/src/DeviceOrientationEventWrappingImplementation.dart

Index: client/html/src/DeviceOrientationEventWrappingImplementation.dart
diff --git a/client/html/src/DeviceOrientationEventWrappingImplementation.dart b/client/html/src/DeviceOrientationEventWrappingImplementation.dart
new file mode 100644
index 0000000000000000000000000000000000000000..6ea81e7aef12482aecd38d7d47240b13ef7b35a7
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+++ b/client/html/src/DeviceOrientationEventWrappingImplementation.dart
@@ -0,0 +1,22 @@
+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+class DeviceOrientationEventWrappingImplementation extends EventWrappingImplementation implements DeviceOrientationEvent {
+  DeviceOrientationEventWrappingImplementation._wrap(ptr) : super._wrap(ptr);
+
+  factory DeviceOrientationEventWrappingImplementation(String type,
+      double alpha, double beta, double gamma, [bool canBubble = false,
+      bool cancelable = false]) {
+    final e = dom.document.createEvent("DeviceOrientationEvent");
+    e.initDeviceOrientationEvent(
+        type, canBubble, cancelable, alpha, beta, gamma);
+    return LevelDom.wrapDeviceOrientationEvent(e);
+  }
+
+  num get alpha() => _ptr.alpha;
+
+  num get beta() => _ptr.beta;
+
+  num get gamma() => _ptr.gamma;
+}