Fill CacheEntry.modificationTime for implicit sources.

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 661 matching lines @@
       return true;
     }
     return source.exists();
   }
 
   @override
   CacheEntry getCacheEntry(AnalysisTarget target) {
     CacheEntry entry = _cache.get(target);
     if (entry == null) {
       entry = new CacheEntry(target);
+      if (target is Source) {
+        entry.modificationTime = getModificationStamp(target);

[Brian Wilkerson, 2015/05/22 18:58:52]

Unless we explicitly want to not have a modification time for non-Source
targets, this could be:

Source source = target.source;
if (source != null) {
  entry.modificationTime = getModificationStamp(source);
}

[scheglov, 2015/05/22 19:17:30]

We use "modificationTime" only "_validateCacheConsistency", and do this only for
sources.
So, it seems that modificationTime for non-sources would not be used, at least
currently.

+      }
       _cache.put(entry);
     }
     return entry;
   }
 
   @override
   CompilationUnitElement getCompilationUnitElement(
       Source unitSource, Source librarySource) {
     AnalysisTarget target = new LibrarySpecificUnit(librarySource, unitSource);
     return _cache.getValue(target, COMPILATION_UNIT_ELEMENT);
@@ skipping 1302 matching lines @@
     PendingFuture pendingFuture =
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
     }
     return pendingFuture.future;
   }
 }