Extract 'computeLineStarts' utility.

pkg/analyzer/lib/src/task/html.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.
 
 library analyzer.src.task.html;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
@@ skipping 342 matching lines @@
    */
   static ParseHtmlTask createTask(
       AnalysisContext context, AnalysisTarget target) {
     return new ParseHtmlTask(context, target);
   }
 
   /**
    * Compute [LineInfo] for the given [content].
    */
   static LineInfo _computeLineInfo(String content) {
-    List<int> lineStarts = <int>[0];
-    for (int index = 0; index < content.length; index++) {
-      if (content.codeUnitAt(index) == 0x0A) {
-        lineStarts.add(index + 1);
-      }
-    }
+    List<int> lineStarts = StringUtilities.computeLineStarts(content);
     return new LineInfo(lineStarts);
   }
 }
 
 /**
  * A fragment of a [DartScript].
  */
 class ScriptFragment {
   /**
    * The offset of the first character of the fragment, relative to the start of
@@ skipping 16 matching lines @@
    * The content of the fragment.
    */
   final String content;
 
   /**
    * Initialize a newly created script fragment to have the given [offset] and
    * [content].
    */
   ScriptFragment(this.offset, this.line, this.column, this.content);
 }