All strong mode cleaning of dart2js.

tests/compiler/dart2js/sourcemaps/data/invokes_test_file.dart

 // Copyright (c) 2015, 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.
 
 // Test file for testing source mappings of invocations.
 
 var counter = 0;
 
 main(args) {
   counter++;
@@ skipping 27 matching lines @@
   (parameter)();
 
   parameter.dynamicInvoke();
   new C(parameter).instanceInvokes();
 }
 
 toplevelFunction() {
   counter++;
 }
 
-var toplevelField = () {
+dynamic toplevelField = () {
   counter++;
 };
 
 final toplevelFinalField = toplevelFunction;
 
 const toplevelConstField = toplevelFunction;
 
 get toplevelGetter => () {
       counter++;
     };
 
 typedef F();
 
 class B {
   B(parameter);
 
   superMethod() {
     counter++;
   }
 
-  var superField = () {
+  dynamic superField = () {
     counter++;
   };
 
   get superGetter => () {
         counter++;
       };
 }
 
 class C<T> extends B {
   C(parameter) : super(parameter);
 
   static staticFunction() {
     counter++;
   }
 
-  static var staticField = () {
+  static dynamic staticField = () {
     counter++;
   };
 
   static final staticFinalField = staticFunction;
 
   static const staticConstField = staticFunction;
 
   static get staticGetter => () {
         counter++;
       };
 
   instanceMethod() {
     counter++;
   }
 
-  var instanceField = () {
+  dynamic instanceField = () {
     counter++;
   };
 
   get instanceGetter => () {
         counter++;
       };
 
   instanceInvokes() {
     instanceMethod();
     this.instanceMethod();
     instanceField();
     this.instanceField();
     instanceGetter();
     this.instanceGetter();
 
     super.superMethod();
     super.superField();
     super.superGetter();
 
     C();
     dynamic();
     F();
     T();
   }
 }