Fixes #179 -- compile error if editing files during server mode

bin/edit_files.dart

 #!/usr/bin/env 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.
 
 /// Command line tool to write checker errors as inline comments in the source
 /// code of the program. This tool requires the info.json file created by
 /// running devc.dart passing the arguments
 /// --dump-info --dump-info-file info.json
 
 library dev_compiler.bin.edit_files;
 
 import 'dart:io';
 import 'dart:convert';
 
+import 'package:analyzer/src/generated/source.dart' show Source;
 import 'package:args/args.dart';
 import 'package:cli_util/cli_util.dart' show getSdkDir;
 import 'package:source_maps/refactor.dart';
 import 'package:source_span/source_span.dart';
 
 import 'package:dev_compiler/src/options.dart';
 import 'package:dev_compiler/src/summary.dart';
 import 'package:dev_compiler/src/checker/resolver.dart' show TypeResolver;
 
 final ArgParser argParser = new ArgParser()
@@ skipping 30 matching lines @@
 
 class EditFileSummaryVisitor extends RecursiveSummaryVisitor {
   var _files = new Map<String, TextEditTransaction>();
   TypeResolver typeResolver;
   String level;
   String checkoutFilesExecutable;
   String checkoutFilesArg;
   RegExp includePattern;
   RegExp excludePattern;
 
+  final Map<Uri, Source> _sources = <Uri, Source>{};
+
   EditFileSummaryVisitor(this.typeResolver, this.level,
       this.checkoutFilesExecutable, this.checkoutFilesArg, this.includePattern,
       this.excludePattern);
 
   TextEditTransaction getEdits(String name) => _files.putIfAbsent(name, () {
     var fileContents = new File(name).readAsStringSync();
     return new TextEditTransaction(fileContents, new SourceFile(fileContents));
   });
 
+  /// Find the corresponding [Source] for [uri].
+  Source findSource(Uri uri) {
+    var source = _sources[uri];
+    if (source != null) return source;
+    return _sources[uri] = typeResolver.context.sourceFactory.forUri('$uri');
+  }
+
   @override
   void visitMessage(MessageSummary message) {
     var uri = message.span.sourceUrl;
     // Ignore dart: libraries.
     if (uri.scheme == 'dart') return;
     if (level != null) {
       // Filter out messages with lower severity.
       switch (message.level) {
         case "info":
           if (level != "info") return;
           break;
         case "warning":
           if (level == "severe") return;
           break;
       }
     }
-    var fullName = typeResolver.findSource(uri).fullName;
+    var fullName = findSource(uri).fullName;
     if (includePattern != null && !includePattern.hasMatch(fullName)) return;
     if (excludePattern != null && excludePattern.hasMatch(fullName)) return;
     var edits = getEdits(fullName);
     edits.edit(message.span.start.offset, message.span.start.offset,
         " /* DDC:${message.level}: ${message.kind}, ${message.message} */ ");
   }
 
   void build() {
     if (checkoutFilesExecutable != null) {
       Process.runSync(
@@ skipping 38 matching lines @@
   var includePattern = (args['include-pattern'] != null)
       ? new RegExp(args['include-pattern'])
       : null;
 
   var visitor = new EditFileSummaryVisitor(typeResolver, args['level'],
       args['checkout-files-executable'], args['checkout-files-arg'],
       includePattern, excludePattern);
   summary.accept(visitor);
   visitor.build();
 }