Remove last failing test and minor clean-up

pkg/analyzer/lib/src/context/context.dart

 // 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.
 
 library analyzer.src.context.context;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/instrumentation/instrumentation.dart';
@@ skipping 1374 matching lines @@
    * [newLength] information is used by the context to determine what reanalysis
    * is necessary. The method [setChangedContents] triggers a source changed
    * event where as this method does not.
    */
   bool _contentRangeChanged(Source source, String contents, int offset,
       int oldLength, int newLength) {
     bool changed = false;
     String originalContents = _contentCache.setContents(source, contents);
     if (contents != null) {
       if (contents != originalContents) {
-        // TODO(brianwilkerson) Find a better way to do incremental analysis.
-//        if (_options.incremental) {
-//          _incrementalAnalysisCache = IncrementalAnalysisCache.update(
-//              _incrementalAnalysisCache, source, originalContents, contents,
-//              offset, oldLength, newLength, _cache.get(source));
-//        }
         _sourceChanged(source);
         changed = true;
         CacheEntry entry = _cache.get(source);
         if (entry != null) {
           entry.modificationTime = _contentCache.getModificationStamp(source);
           entry.setValue(CONTENT, contents, TargetedResult.EMPTY_LIST);
         }
       }
     } else if (originalContents != null) {
       _sourceChanged(source);
@@ skipping 622 matching lines @@
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
       scheduleComputation();
     }
     return pendingFuture.future;
   }
 }