Get rid of a lot of () for getters.

lib/html/src/DeviceOrientationEventWrappingImplementation.dart

 // 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 = true,
       bool cancelable = true]) {
     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 alpha => _ptr.alpha;
 
-  num get beta() => _ptr.beta;
+  num get beta => _ptr.beta;
 
-  num get gamma() => _ptr.gamma;
+  num get gamma => _ptr.gamma;
 }