Fix initialize transformer crash on some programs

lib/build/initializer_plugin.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.
 library initialize.build.initializer_plugin;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:barback/barback.dart';
 import 'package:code_transformers/resolver.dart';
 import 'package:initialize/transformer.dart';
@@ skipping 213 matching lines @@
         first = false;
         buffer.write(buildExpression(entry.key, pluginData));
         buffer.write(': ');
         buffer.write(buildExpression(entry.value, pluginData));
       }
       buffer.write('}');
     } else if (expression is Identifier) {
       var element = expression.bestElement;
       if (element == null || !element.isPublic) {
         logger.error('Private constants are not supported in intializer '
-        'constructors, found $element.');
+            'constructors, found $element.');
       }
       libraryPrefixes.putIfAbsent(
           element.library, () => 'i${libraryPrefixes.length}');
 
       buffer.write('${libraryPrefixes[element.library]}.');
       if (element is ClassElement) {
         buffer.write(element.name);
       } else if (element is PropertyAccessorElement) {
         var variable = element.variable;
         if (variable is FieldElement) {
@@ skipping 31 matching lines @@
     return buffer.toString();
   }
 
   // Returns an expression for a string value. Wraps it in single quotes and
   // escapes existing single quotes and escapes.
   _stringValue(String value) {
     value = value.replaceAll(r'\', r'\\').replaceAll(r"'", r"\'");
     return "'$value'";
   }
 }