Ignore unused classes when constructing set for deferred loading.

sdk/lib/_internal/compiler/implementation/deferred_load.dart

 // Copyright (c) 2013, 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 'dart:collection'
        show LinkedHashMap,
             LinkedHashSet;
 
@@ skipping 65 matching lines @@
       if (deferredLibraries.isEmpty) return;
 
       // TODO(ahe): Enforce the following invariants on
       // [deferredElements] and [eagerElements]:
       // 1. Only static or top-level elements are recorded.
       // 2. Only implementation is stored.
       Map<LibraryElement, Set<Element>> deferredElements =
           new LinkedHashMap<LibraryElement, Set<Element>>();
       Set<Element> eagerElements = new LinkedHashSet<Element>();
 
-      // Iterate through the local members of the main script.  Create
+      // Iterate through live local members of the main script.  Create
       // a root-set of elements that must be loaded eagerly
       // (everything that is directly referred to from the main
       // script, but not imported from a deferred library), as well as
       // root-sets for deferred libraries.
       mainApp.forEachLocalMember((Element e) {
-        for (Element dependency in allElementsResolvedFrom(e)) {
-          if (isExplicitlyDeferred(dependency)) {
-            Set<Element> deferredElementsFromLibrary =
-                deferredElements.putIfAbsent(
-                    dependency.getLibrary(),
-                    () => new LinkedHashSet<Element>());
-            deferredElementsFromLibrary.add(dependency);
-          } else if (dependency.getLibrary() != mainApp) {
-            eagerElements.add(dependency.implementation);
+        if (compiler.enqueuer.resolution.isLive(e)) {
+          for (Element dependency in allElementsResolvedFrom(e)) {
+            if (isExplicitlyDeferred(dependency)) {
+              Set<Element> deferredElementsFromLibrary =
+                  deferredElements.putIfAbsent(
+                      dependency.getLibrary(),
+                      () => new LinkedHashSet<Element>());
+              deferredElementsFromLibrary.add(dependency);
+            } else if (dependency.getLibrary() != mainApp) {
+              eagerElements.add(dependency.implementation);
+            }
           }
         }
       });
 
       // Also add "global" dependencies to the eager root-set.  These
       // are things that the backend need but cannot associate with a
       // particular element, for example, startRootIsolate.  This set
       // also contains elements for which we lack precise information.
       eagerElements.addAll(compiler.globalDependencies.otherDependencies);
 
@@ skipping 131 matching lines @@
         compiler.enqueuer.resolution.getCachedElements(element);
     if (elements == null) return new LinkedHashSet<Element>();
     Node node = element.parseNode(compiler);
     if (node == null) return new LinkedHashSet<Element>();
     var collector = new DependencyCollector(elements, compiler);
     node.accept(collector);
     collector.dependencies.addAll(elements.otherDependencies);
     return collector.dependencies;
   }
 }