Produce LINE_INFO for HTML files.

pkg/analyzer/lib/src/generated/source.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 engine.source;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 254 matching lines @@
   final int columnNumber;
 
   /**
    * Initialize a newly created location to represent the location of the character at the given
    * line and column position.
    *
    * @param lineNumber the one-based index of the line containing the character
    * @param columnNumber the one-based index of the column containing the character
    */
   LineInfo_Location(this.lineNumber, this.columnNumber);
+
+  @override
+  String toString() => '$lineNumber:$columnNumber';
 }
 
 /**
  * Instances of interface `LocalSourcePredicate` are used to determine if the given
  * [Source] is "local" in some sense, so can be updated.
  */
 abstract class LocalSourcePredicate {
   /**
    * Instance of [LocalSourcePredicate] that always returns `false`.
    */
@@ skipping 789 matching lines @@
   Source resolveAbsolute(Uri uri, [Uri actualUri]);
 
   /**
    * Return an absolute URI that represents the given [source], or `null` if a
    * valid URI cannot be computed.
    *
    * The computation should be based solely on [source.fullName].
    */
   Uri restoreAbsolute(Source source) => null;
 }