Re-land "Search for main in the exported names of the main library, not in the library itself."

sdk/lib/_internal/compiler/implementation/elements/elements.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.
 
 library elements;
 
 
 import '../tree/tree.dart';
 import '../util/util.dart';
 import '../resolution/resolution.dart';
@@ skipping 676 matching lines @@
   void addMember(Element element, DiagnosticListener listener);
   void addToScope(Element element, DiagnosticListener listener);
 
   // TODO(kasperl): Get rid of this method.
   Iterable<Element> getNonPrivateElementsInScope();
 
   void setExports(Iterable<Element> exportedElements);
 
   Element find(String elementName);
   Element findLocal(String elementName);
+  Element findExported(String elementName);
   void forEachExport(f(Element element));
 
   bool hasLibraryName();
   String getLibraryName();
   String getLibraryOrScriptName();
 
   int compareTo(LibraryElement other);
 }
 
 abstract class PrefixElement extends Element {
@@ skipping 272 matching lines @@
   int get resolutionState;
   Token get beginToken;
   Token get endToken;
 
   // TODO(kasperl): Try to get rid of these.
   void set annotatedElement(Element value);
   void set resolutionState(int value);
 
   MetadataAnnotation ensureResolved(Compiler compiler);
 }