pkg/string_scanner: code format, expanded dependency constraint on unittest

lib/src/line_scanner.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 string_scanner.line_scanner;
 
 import 'string_scanner.dart';
 
 /// A subclass of [StringScanner] that tracks line and column information.
 class LineScanner extends StringScanner {
@@ skipping 22 matching lines @@
     super.position = state.position;
     _line = state.line;
     _column = state.column;
   }
 
   set position(int newPosition) {
     var oldPosition = position;
     super.position = newPosition;
 
     if (newPosition > oldPosition) {
-      var newlines = "\n".allMatches(string.substring(oldPosition, newPosition))
-          .toList();
+      var newlines =
+          "\n".allMatches(string.substring(oldPosition, newPosition)).toList();
       _line += newlines.length;
       if (newlines.isEmpty) {
         _column += newPosition - oldPosition;
       } else {
         _column = newPosition - newlines.last.end;
       }
     } else {
-      var newlines = "\n".allMatches(string.substring(newPosition, oldPosition))
-          .toList();
+      var newlines =
+          "\n".allMatches(string.substring(newPosition, oldPosition)).toList();
       _line -= newlines.length;
       if (newlines.isEmpty) {
         _column -= oldPosition - newPosition;
       } else {
         _column = newPosition - string.lastIndexOf("\n", newPosition) - 1;
       }
     }
   }
 
   LineScanner(String string, {sourceUrl, int position})
       : super(string, sourceUrl: sourceUrl, position: position);
 
   int readChar() {
     var char = super.readChar();
     if (char == 0xA) {
       _line += 1;
       _column = 0;
     } else {
       _column += 1;
     }
     return char;
   }
 
   bool scan(Pattern pattern) {
-    var oldPosition = position;
     if (!super.scan(pattern)) return false;
 
     var newlines = "\n".allMatches(lastMatch[0]).toList();
     _line += newlines.length;
     if (newlines.isEmpty) {
       _column += lastMatch[0].length;
     } else {
       _column = lastMatch[0].length - newlines.last.end;
     }
 
@@ skipping 10 matching lines @@
   final int position;
 
   /// The zero-based line number of the scanner in this state.
   final int line;
 
   /// The zero-based column number of the scanner in this state.
   final int column;
 
   LineScannerState._(this._scanner, this.position, this.line, this.column);
 }