Move main and isolate handling to enqueuer listeners.

pkg/compiler/lib/src/common_elements.dart

 // Copyright (c) 2014, 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.
 
 // TODO(sigmund): rename and move to common/elements.dart
 library dart2js.type_system;
 
 import 'common.dart';
 import 'elements/types.dart';
 import 'elements/entities.dart';
@@ skipping 193 matching lines @@
 
   /// Returns `true` if [element] is a superclass of `List`.
   bool isListSupertype(ClassEntity element);
 }
 
 /// Interface for accessing libraries, classes and members.
 ///
 /// The environment makes private and injected members directly available and
 /// should therefore not be used to determine scopes.
 abstract class ElementEnvironment {
+  /// Returns the main library for the compilation.
+  LibraryEntity get mainLibrary;
+
+  /// Returns the main method for the compilation.
+  FunctionEntity get mainFunction;
+
+  /// Lookup the library with the canonical [uri], fail if the library is
+  /// missing and [required];
   LibraryEntity lookupLibrary(Uri uri, {bool required: false});
 
   /// Lookup the class [name] in [library], fail if the class is missing and
   /// [required].
   ClassEntity lookupClass(LibraryEntity library, String name,
       {bool required: false});
 
   /// Lookup the member [name] in [library], fail if the class is missing and
   /// [required].
   MemberEntity lookupLibraryMember(LibraryEntity library, String name,
@@ skipping 268 matching lines @@
   }
 
   @override
   InterfaceType streamType([DartType elementType]) {
     if (elementType == null) {
       return getRawType(streamClass);
     }
     return createInterfaceType(streamClass, [elementType]);
   }
 }