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

lib/src/info.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.
 
 /// Defines static information collected by the type checker and used later by
 /// emitters to generate code.
 library dev_compiler.src.info;
 
 import 'dart:mirrors';
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/error.dart' as analyzer;
 import 'package:analyzer/src/generated/scanner.dart'
     show Token, TokenType, SyntheticStringToken;
 import 'package:logging/logging.dart' show Level;
 
 import 'package:dev_compiler/src/checker/rules.dart';
 import 'package:dev_compiler/src/utils.dart' as utils;
 
 import 'report.dart' show Message;
 
 /// Represents a summary of the results collected by running the program
@@ skipping 700 matching lines @@
   for (var cls in declarations.where((d) => d is ClassMirror)) {
     if (cls.isSubtypeOf(infoMirror)) {
       allTypes.add(cls);
       baseTypes.add(cls.superclass);
     }
   }
   allTypes.removeAll(baseTypes);
   return new List<Type>.from(allTypes.map((mirror) => mirror.reflectedType))
     ..sort((t1, t2) => '$t1'.compareTo('$t2'));
 }();
+
+class AnalyzerError extends Message {
+  factory AnalyzerError.from(analyzer.AnalysisError error) {
+    var severity = error.errorCode.type.severity;
+    var isError = severity == analyzer.ErrorSeverity.ERROR;
+    var level = isError ? Level.SEVERE : Level.WARNING;
+    int begin = error.offset;
+    int end = begin + error.length;
+    return new AnalyzerError(error.message, level, begin, end);
+  }
+
+  const AnalyzerError(String message, Level level, int begin, int end)
+      : super('[from analyzer]: $message', level, begin, end);
+}