Revert "Model 'await for' as an explicit node in tree and fix its handling."

pkg/compiler/lib/src/compiler.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;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 512 matching lines @@
   void registerAsyncMarker(FunctionElement element,
                              Enqueuer enqueuer,
                              Registry registry) {}
 }
 
 /// Backend callbacks function specific to the resolution phase.
 class ResolutionCallbacks {
   /// Register that [node] is a call to `assert`.
   void onAssert(Send node, Registry registry) {}
 
-  /// Register that an 'await for' has been seen.
-  void onAsyncForIn(AsyncForIn node, Registry registry) {}
-
   /// Called during resolution to notify to the backend that the
   /// program uses string interpolation.
   void onStringInterpolation(Registry registry) {}
 
   /// Called during resolution to notify to the backend that the
   /// program has a catch statement.
   void onCatchStatement(Registry registry) {}
 
   /// Called during resolution to notify to the backend that the
   /// program explicitly throws an exception.
@@ skipping 1868 matching lines @@
     return futureClass.computeType(compiler).createInstantiation([elementType]);
   }
 
   @override
   InterfaceType streamType([DartType elementType = const DynamicType()]) {
     return streamClass.computeType(compiler).createInstantiation([elementType]);
   }
 }
 
 typedef void InternalErrorFunction(Spannable location, String message);