Extract 'computeLineStarts' utility.

pkg/analyzer/lib/src/task/html.dart

Index: pkg/analyzer/lib/src/task/html.dart
diff --git a/pkg/analyzer/lib/src/task/html.dart b/pkg/analyzer/lib/src/task/html.dart
index b603f1f7139c2dc6c96f6cc5abfa232b86155334..c789c6e086e313badf3a093b321a43aaa67f2183 100644
--- a/pkg/analyzer/lib/src/task/html.dart
+++ b/pkg/analyzer/lib/src/task/html.dart
@@ -12,6 +12,7 @@ import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_string.dart';
 import 'package:analyzer/src/plugin/engine_plugin.dart';
 import 'package:analyzer/src/task/general.dart';
 import 'package:analyzer/task/dart.dart';
@@ -360,12 +361,7 @@ class ParseHtmlTask extends SourceBasedAnalysisTask {
    * 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 = computeLineStarts(content);
     return new LineInfo(lineStarts);
   }
 }