Deferred (aka lazy) loading of static functions.

dart/sdk/lib/async/async.dart

Index: dart/sdk/lib/async/async.dart
diff --git a/dart/sdk/lib/async/async.dart b/dart/sdk/lib/async/async.dart
index 80716fb1806fe12f7d609f47c01a2d60308ce608..8704d8af3af80dffeb8d6d2243b454973dca88b3 100644
--- a/dart/sdk/lib/async/async.dart
+++ b/dart/sdk/lib/async/async.dart
@@ -4,6 +4,8 @@
 
 library dart.async;
 
+import 'dart:isolate';
+
 part 'async_error.dart';
 part 'future.dart';
 part 'future_impl.dart';
@@ -12,3 +14,11 @@ part 'stream_controller.dart';
 part 'stream_impl.dart';
 part 'stream_pipe.dart';
 part 'timer.dart';
+
+/**
+ * Ensure that [libraryName] has been loaded.
+ *
+ * The returned future if this invocation of [load] caused the library
+ * to be loaded.
+ */
+external Future<bool> load(String libraryName, {String uri});