Reapply "Refactoring if block-information."

lib/compiler/implementation/native_handler.dart

 // Copyright (c) 2012, 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.
 
 #library('native');
 #import('dart:uri');
 #import('leg.dart');
 #import('elements/elements.dart');
 #import('scanner/scannerlib.dart');
 #import('ssa/ssa.dart');
@@ skipping 322 matching lines @@
 
 // If a method is overridden, we must check if the prototype of
 // 'this' has the method available. Otherwise, we may end up
 // calling the method from the super class. If the method is not
 // available, we make a direct call to Object.prototype.$methodName.
 // This method will patch the prototype of 'this' to the real method.
 void generateMethodWithPrototypeCheck(Compiler compiler,
                                       StringBuffer buffer,
                                       String methodName,
                                       String code,
-                                      String parameters) {     
+                                      String parameters) {
   buffer.add("  if (Object.getPrototypeOf(this).hasOwnProperty");
   buffer.add("('$methodName')) {\n");
   buffer.add("  $code");
   buffer.add("  } else {\n");
   buffer.add("    return Object.prototype.$methodName.call(this");
   buffer.add(parameters == '' ? '' : ', $parameters');
   buffer.add(");\n");
   buffer.add("  }\n");
 }