Implement await for statement

runtime/vm/object_store.cc

 // 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.
 
 #include "vm/object_store.h"
 
 #include "vm/exceptions.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 19 matching lines @@
     mint_type_(Type::null()),
     bigint_class_(Class::null()),
     double_class_(Class::null()),
     double_type_(Type::null()),
     float32x4_type_(Type::null()),
     int32x4_type_(Type::null()),
     float64x2_type_(Type::null()),
     string_type_(Type::null()),
     future_class_(Class::null()),
     completer_class_(Class::null()),
+    stream_iterator_class_(Class::null()),
     one_byte_string_class_(Class::null()),
     two_byte_string_class_(Class::null()),
     external_one_byte_string_class_(Class::null()),
     external_two_byte_string_class_(Class::null()),
     bool_type_(Type::null()),
     bool_class_(Class::null()),
     array_class_(Class::null()),
     array_type_(Type::null()),
     immutable_array_class_(Class::null()),
     growable_object_array_class_(Class::null()),
@@ skipping 125 matching lines @@
 
   const Library& async_lib = Library::Handle(async_library());
   ASSERT(!async_lib.IsNull());
   Class& cls = Class::Handle(isolate);
   cls = async_lib.LookupClass(Symbols::Future());
   ASSERT(!cls.IsNull());
   set_future_class(cls);
   cls = async_lib.LookupClass(Symbols::Completer());
   ASSERT(!cls.IsNull());
   set_completer_class(cls);
+  cls = async_lib.LookupClass(Symbols::StreamIterator());
+  ASSERT(!cls.IsNull());
+  set_stream_iterator_class(cls);
 }
 
 }  // namespace dart