dart2js: fix dependency tracking for deferred loading when types are only used

pkg/compiler/lib/src/deferred_load.dart

 // Copyright (c) 2014, 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 deferred_load;
 
 import 'constants/values.dart' show
     ConstantValue,
     ConstructedConstantValue,
     DeferredConstantValue,
@@ skipping 262 matching lines @@
 
       assert(treeElements != null);
 
       for (Element dependency in treeElements.allElements) {
         if (dependency.isLocal && !dependency.isFunction) continue;
         if (dependency.isErroneous) continue;
         if (dependency.isTypeVariable) continue;
 
         elements.add(dependency);
       }
+
+      void registerTypeArgumentsAsDependencies(DartType type) {
+        Element dependency = type.element;
+        if (dependency == null || dependency.isErroneous ||
+            dependency.isTypeVariable) {
+          return;
+        }
+        elements.add(dependency);
+        if (type is GenericType) {
+          type.typeArguments.forEach(registerTypeArgumentsAsDependencies);
+        }
+      }
+
+      treeElements.forEachType((Node node, DartType type) {
+        if (node is NewExpression) registerTypeArgumentsAsDependencies(type);
+      });
+
       treeElements.forEachConstantNode((Node node, _) {
         // Explicitly depend on the backend constants.
         ConstantValue value =
             backend.constants.getConstantValueForNode(node, treeElements);
         if (value != null) {
           // TODO(johnniwinther): Assert that all constants have values when
           // these are directly evaluated.
           constants.add(value);
         }
       });
@@ skipping 591 matching lines @@
         _importingLibrary = importingLibrary;
 
   String get importingLibraryName {
     String libraryName = _importingLibrary.getLibraryName();
     return libraryName == ""
       ? "<unnamed>"
       : libraryName;
   }
 
 }