Fix to ensure no breaks after new and general zero-length space support (dartbug.com/16379).

pkg/analyzer/lib/src/services/writer.dart

 // Copyright (c) 2013, 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 source_writer;
 
 
 
 class Line {
 
   final List<LineToken> tokens = <LineToken>[];
   final bool useTabs;
   final int spacesPerIndent;
   final int indentLevel;
   final LinePrinter printer;
 
   Line({this.indentLevel: 0, this.useTabs: false, this.spacesPerIndent: 2,
       this.printer: const SimpleLinePrinter()}) {
     if (indentLevel > 0) {
       indent(indentLevel);
     }
   }
 
   void addSpace() {
     addSpaces(1);
   }
 
   void addSpaces(int n, {breakWeight: DEFAULT_SPACE_WEIGHT}) {
-    if (n > 0) {
-      tokens.add(new SpaceToken(n, breakWeight: breakWeight));
-    }
+    tokens.add(new SpaceToken(n, breakWeight: breakWeight));
   }
 
   void addToken(LineToken token) {
     tokens.add(token);
   }
 
   bool isEmpty() => tokens.isEmpty;
 
   bool isWhitespace() => tokens.every((tok) => tok is SpaceToken);
 
@@ skipping 388 matching lines @@
 
 String getTabs(int n) => n < TABS.length ? TABS[n] : repeat('\t', n);
 
 String repeat(String ch, int times) {
   var sb = new StringBuffer();
   for (var i = 0; i < times; ++i) {
     sb.write(ch);
   }
   return sb.toString();
 }