Remove more dead code

pkg/analysis_server/lib/src/utilities/average.dart

Index: pkg/analysis_server/lib/src/utilities/average.dart
diff --git a/pkg/analysis_server/lib/src/utilities/average.dart b/pkg/analysis_server/lib/src/utilities/average.dart
deleted file mode 100644
index 22cf299b55beb03bd26cfaa92212dcb28c54bfa5..0000000000000000000000000000000000000000
--- a/pkg/analysis_server/lib/src/utilities/average.dart
+++ /dev/null
@@ -1,28 +0,0 @@
-// 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.
-
-/// Simple rolling average sample counter.
-class Average {
-  num _val;
-  final int _sampleCount;
-
-  /// Create an average with the given (optional) sample count size.
-  Average([this._sampleCount = 20]);
-
-  /// The current average.
-  num get value => _val ?? 0;
-
-  /// Add the given [sample].
-  void addSample(num sample) {
-    if (_val == null) {
-      _val = sample;
-    } else {
-      _val = _val * ((_sampleCount - 1) / _sampleCount) +
-          sample * (1 / _sampleCount);
-    }
-  }
-
-  @override
-  String toString() => 'average: $value';
-}