Remove Compiler.mainApp and Compiler.mainFunction

pkg/compiler/lib/src/js_emitter/full_emitter/emitter.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.
 
 library dart2js.js_emitter.full_emitter;
 
 import 'dart:collection' show HashMap;
 import 'dart:convert';
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
@@ skipping 1088 matching lines @@
     compiler.dumpInfoTask.registerElementAst(library, metadata);
     compiler.dumpInfoTask.registerElementAst(library, initializer);
 
     List<jsAst.Expression> parts = <jsAst.Expression>[];
     parts
       ..add(js.string(libraryName))
       ..add(js.string(uri.toString()))
       ..add(metadata == null ? new jsAst.ArrayHole() : metadata)
       ..add(js('#', namer.globalObjectForLibrary(library)))
       ..add(initializer);
-    if (library == compiler.mainApp) {
+    if (library == _closedWorld.elementEnvironment.mainLibrary) {
       parts.add(js.number(1));
     }
 
     return new jsAst.ArrayInitializer(parts);
   }
 
   void assemblePrecompiledConstructor(
       OutputUnit outputUnit,
       jsAst.Name constructorName,
       jsAst.Expression constructorAst,
@@ skipping 852 matching lines @@
     // data.
     mapping["_comment"] = "This mapping shows which compiled `.js` files are "
         "needed for a given deferred library import.";
     mapping.addAll(compiler.deferredLoadTask.computeDeferredMap());
     compiler.outputProvider(
         compiler.options.deferredMapUri.path, '', OutputType.info)
       ..add(const JsonEncoder.withIndent("  ").convert(mapping))
       ..close();
   }
 }