Deferred (aka lazy) loading of static functions.

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

 // Copyright (c) 2012, 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.
 
 part of dart2js;
 
 /**
  * [CompilerTask] for loading libraries and setting up the import/export scopes.
  *
  * The library loader uses four different kinds of URIs in different parts of
@@ skipping 778 matching lines @@
       node.registerImports(compiler);
     });
   }
 
   /**
    * Registers that [library] depends on [loadedLibrary] through [tag].
    */
   void registerDependency(LibraryElement library,
                           LibraryDependency tag,
                           LibraryElement loadedLibrary) {
+    if (tag != null) {
+      library.resolvedTag(tag, loadedLibrary);
+    }
     if (tag is Export) {
       // [loadedLibrary] is exported by [library].
       LibraryDependencyNode exportingNode = nodeMap[library];
       if (loadedLibrary.exportsHandled) {
         // Export scope already computed on [loadedLibrary].
         var combinatorFilter = new CombinatorFilter.fromTag(tag);
         exportingNode.registerHandledExports(loadedLibrary, combinatorFilter);
         return;
       }
       LibraryDependencyNode exportedNode = nodeMap[loadedLibrary];
@@ skipping 19 matching lines @@
   }
 
   /**
    * Registers all top-level entities of [library] as starting point for the
    * fixed-point computation of the import/export scopes.
    */
   void registerLibraryExports(LibraryElement library) {
     nodeMap[library].registerInitialExports();
   }
 }