Updating code_transformers to not fail on syntax errors

pkg/code_transformers/lib/src/resolver_impl.dart

 // Copyright (c) 2014, 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 code_transformer.src.resolver_impl;
 
 import 'dart:async';
 import 'package:analyzer/analyzer.dart' show parseCompilationUnit;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 271 matching lines @@
 
   /// The file contents.
   String _contents;
 
   _AssetBasedSource(this.assetId, this._resolver);
 
   /// Update the dependencies of this source. This parses [contents] but avoids
   /// any analyzer resolution.
   void updateDependencies(String contents) {
     if (contents == _contents) return;
-    var unit = parseCompilationUnit(contents);
+    var unit = parseCompilationUnit(contents, suppressErrors: true);
     _dependentAssets = unit.directives
         .where((d) => (d is ImportDirective || d is PartDirective ||
             d is ExportDirective))
         .map((d) => _resolve(assetId, d.uri.stringValue, _logger,
               _getSpan(d, contents)))
         .where((id) => id != null).toSet();
   }
 
   /// Update the contents of this file with [contents].
   ///
@@ skipping 283 matching lines @@
 
   void apply(ChangeSet changeSet) {
     if (!source.updateContents(content)) return;
     if (source._revision == 1 && source._contents != null) {
       changeSet.addedSource(source);
     } else {
       changeSet.changedSource(source);
     }
   }
 }