Adding isNotEmpty property to collection and string.

sdk/lib/_internal/compiler/implementation/code_buffer.dart

 // Copyright (c) 2012, 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.
 
 part of dart2js;
 
 class CodeBuffer implements StringBuffer {
   StringBuffer buffer;
   List<CodeBufferMarker> markers;
   int lastBufferOffset = 0;
   int mappedRangeCounter = 0;
 
   CodeBuffer()
       : buffer = new StringBuffer(),
         markers = new List<CodeBufferMarker>();
 
   int get length => buffer.length;
 
   bool get isEmpty {
     return buffer.isEmpty;
   }
 
+  bool get isNotEmpty => !isEmpty;
+
   CodeBuffer add(var object) {
     write(object);
     return this;
   }
   /**
    * Converts [object] to a string and adds it to the buffer. If [object] is a
    * [CodeBuffer], adds its markers to [markers].
    */
   CodeBuffer write(var object) {
     if (object is CodeBuffer) {
@@ skipping 87 matching lines @@
     });
   }
 }
 
 class CodeBufferMarker {
   final int offsetDelta;
   final sourcePosition;
 
   CodeBufferMarker(this.offsetDelta, this.sourcePosition);
 }