Use 'a' as the first field name rather than 'Q'.

pkg/compiler/lib/src/js_backend/minify_namer.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.
 
 part of js_backend;
 
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
 class MinifyNamer extends Namer with _MinifiedFieldNamer {
@@ skipping 36 matching lines @@
     }
     usedNames.add(freshName);
     return new StringBackedName(freshName);
   }
 
   // From issue 7554.  These should not be used on objects (as instance
   // variables) because they clash with names from the DOM. However, it is
   // OK to use them as fields, as we only access fields directly if we know
   // the receiver type.
   static const List<String> _reservedNativeProperties = const <String>[
-      'Q', 'a', 'b', 'c', 'd', 'e', 'f', 'r', 'x', 'y', 'z',
+      'a', 'b', 'c', 'd', 'e', 'f', 'r', 'x', 'y', 'z', 'Q',
       // 2-letter:
       'ch', 'cx', 'cy', 'db', 'dx', 'dy', 'fr', 'fx', 'fy', 'go', 'id', 'k1',
       'k2', 'k3', 'k4', 'r1', 'r2', 'rx', 'ry', 'x1', 'x2', 'y1', 'y2',
       // 3-letter:
       'add', 'all', 'alt', 'arc', 'CCW', 'cmp', 'dir', 'end', 'get', 'in1',
       'in2', 'INT', 'key', 'log', 'low', 'm11', 'm12', 'm13', 'm14', 'm21',
       'm22', 'm23', 'm24', 'm31', 'm32', 'm33', 'm34', 'm41', 'm42', 'm43',
       'm44', 'max', 'min', 'now', 'ONE', 'put', 'red', 'rel', 'rev', 'RGB',
       'sdp', 'set', 'src', 'tag', 'top', 'uid', 'uri', 'url', 'URL',
       // 4-letter:
@@ skipping 179 matching lines @@
 
   @override
   jsAst.Name instanceFieldPropertyName(Element element) {
     jsAst.Name proposed = _minifiedInstanceFieldPropertyName(element);
     if (proposed != null) {
       return proposed;
     }
     return super.instanceFieldPropertyName(element);
   }
 }
-