Remove unused AnalysisContextImpl.findElementById().

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/src/cancelable_future.dart';
@@ skipping 656 matching lines @@
   bool exists(Source source) {
     if (source == null) {
       return false;
     }
     if (_contentCache.getContents(source) != null) {
       return true;
     }
     return source.exists();
   }
 
-  Element findElementById(int id) {
-    // TODO(brianwilkerson) Implement this.
-    return null;
-//    _ElementByIdFinder finder = new _ElementByIdFinder(id);
-//    try {
-//      MapIterator<AnalysisTarget, cache.CacheEntry> iterator =
-//          _cache.iterator();
-//      while (iterator.moveNext()) {
-//        cache.CacheEntry entry = iterator.value;
-//        if (entry.getValue(SOURCE_KIND) == SourceKind.LIBRARY) {
-//          DartEntry dartEntry = entry;
-//          LibraryElement library = dartEntry.getValue(DartEntry.ELEMENT);
-//          if (library != null) {
-//            library.accept(finder);
-//          }
-//        }
-//      }
-//    } on _ElementByIdFinderException {
-//      return finder.result;
-//    }
-//    return null;
-  }
-
   @override
   cache.CacheEntry getCacheEntry(AnalysisTarget target) {
     cache.CacheEntry entry = _cache.get(target);
     if (entry == null) {
       entry = new cache.CacheEntry();
       _cache.put(target, entry);
     }
     return entry;
   }
 
@@ skipping 1412 matching lines @@
     PendingFuture pendingFuture =
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
     }
     return pendingFuture.future;
   }
 }