Re-implement the status page for the new task model

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 1229 matching lines @@
       buffer.writeln(" removed");
       for (Source source in missingSources) {
         buffer.write("    ");
         buffer.writeln(source.fullName);
       }
       _logInformation(buffer.toString());
     }
     return changedSources.length > 0;
   }
 
+  @deprecated
   @override
   void visitCacheItems(void callback(Source source, SourceEntry dartEntry,
       DataDescriptor rowDesc, CacheState state)) {
     // TODO(brianwilkerson) Figure out where this is used and either remove it
     // or adjust the call sites to use CacheEntry's.
 //    bool hintsEnabled = _options.hint;
 //    bool lintsEnabled = _options.lint;
 //    MapIterator<AnalysisTarget, cache.CacheEntry> iterator = _cache.iterator();
 //    while (iterator.moveNext()) {
 //      Source source = iterator.key;
@@ skipping 45 matching lines @@
 //              continue;
 //            }
 //            callback(librarySource, entry, descriptor,
 //                entry.getStateInLibrary(descriptor, librarySource));
 //          }
 //        }
 //      }
 //    }
   }
 
-  /**
-   * Visit all entries of the content cache.
-   */
+  @override
   void visitContentCache(ContentCacheVisitor visitor) {
     _contentCache.accept(visitor);
   }
 
   /**
    * Add all of the sources contained in the given source [container] to the
    * given list of [sources].
    */
   void _addSourcesInContainer(List<Source> sources, SourceContainer container) {
     for (Source source in _cache.sources) {
@@ skipping 699 matching lines @@
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
       scheduleComputation();
     }
     return pendingFuture.future;
   }
 }