Fix the error message widget

lib/src/summary.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.
 
 /// Summary of error messages produced by a `SummaryReporter`.
 library dev_compiler.src.summary;
 
 import 'dart:collection' show HashSet;
 
-import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
-import 'package:analyzer/src/generated/source.dart' show Source;
 import 'package:source_span/source_span.dart';
 
 /// Summary information computed by the DDC checker.
 abstract class Summary {
   Map toJsonMap();
 
   void accept(SummaryVisitor visitor);
 }
 
 /// Summary for the entire program.
@@ skipping 94 matching lines @@
 
   /// Total lines of code (including all parts of the library).
   int get lines => _lines;
 
   Map toJsonMap() => {
         'library_name': name,
         'messages': messages.map((m) => m.toJsonMap()).toList(),
         'lines': lines,
       };
 
-  void countSourceLines(AnalysisContext context, Source source) {
-    if (_uris.add(source.uri)) {
-      // TODO(jmesserly): parsing is serious overkill for this.
-      // Should be cached, but still.
-      // On the other hand, if we are going to parse, we could get a much better
-      // source lines of code estimate by excluding things like comments,
-      // blank lines, and closing braces.
-      var unit = context.parseCompilationUnit(source);
-      _lines += unit.lineInfo.getLocation(unit.endToken.end).lineNumber;
+  void recordSourceLines(Uri uri, int computeLines()) {
+    if (_uris.add(uri)) {
+      _lines += computeLines();
     }
   }
 
   void accept(SummaryVisitor visitor) => visitor.visitLibrary(this);
 
   static LibrarySummary parse(Map json) =>
       new LibrarySummary(json['library_name'],
-          messages: json['messages'].map(MessageSummary.parse).toList(),
+          messages: new List<MessageSummary>.from(
+              json['messages'].map(MessageSummary.parse)),
           lines: json['lines']);
 }
 
 /// A summary at the level of an HTML file.
 class HtmlSummary implements IndividualSummary {
   /// Unique name used to identify the HTML file.
   final String name;
 
   /// All messages collected on the file.
   final List<MessageSummary> messages;
 
   HtmlSummary(this.name, [List<MessageSummary> messages])
       : messages = messages == null ? <MessageSummary>[] : messages;
 
   Map toJsonMap() =>
       {'name': name, 'messages': messages.map((m) => m.toJsonMap()).toList()};
 
   void accept(SummaryVisitor visitor) => visitor.visitHtml(this);
 
   static HtmlSummary parse(Map json) => new HtmlSummary(
-      json['name'], json['messages'].map(MessageSummary.parse).toList());
+      json['name'],
+      new List<MessageSummary>.from(
+          json['messages'].map(MessageSummary.parse)));
 }
 
 /// A single message produced by the checker.
 class MessageSummary implements Summary {
   /// The kind of message, currently the name of the StaticInfo type.
   final String kind;
 
   /// Level (error, warning, etc).
   final String level;
 
@@ skipping 70 matching lines @@
   }
 
   void visitHtml(HtmlSummary html) {
     for (var msg in html.messages) {
       msg.accept(this);
     }
   }
 
   void visitMessage(MessageSummary message) {}
 }