dartjs: Remove unused isFromMainOutputUnit.

pkg/compiler/lib/src/deferred_load.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 deferred_load;
 
 import 'constants/expressions.dart';
 import 'constants/values.dart' show
     ConstantValue,
     ConstructedConstantValue,
@@ skipping 195 matching lines @@
   ///
   /// For example, if we have two deferred libraries `A` and `B` that both
   /// import a library `C`, then even though elements from `A` and `C` end up in
   /// different output units, there is a non-deferred path between `A` and `C`.
   bool hasOnlyNonDeferredImportPaths(Element from, Element to) {
     OutputUnit outputUnitFrom = outputUnitForElement(from);
     OutputUnit outputUnitTo = outputUnitForElement(to);
     return outputUnitTo.imports.containsAll(outputUnitFrom.imports);
   }
 
-  bool isFromMainOutputUnit(Element element) {
-    return outputUnitForElement(element) == mainOutputUnit;
-  }
-
   void registerConstantDeferredUse(DeferredConstantValue constant,
                                    PrefixElement prefix) {
     OutputUnit outputUnit = new OutputUnit();
     outputUnit.imports.add(prefix.deferredImport);
     _constantToOutputUnit[constant] = outputUnit;
   }
 
   /// Answers whether [element] is explicitly deferred when referred to from
   /// [library].
   bool _isExplicitlyDeferred(Element element, LibraryElement library) {
@@ skipping 663 matching lines @@
         _importingLibrary = importingLibrary;
 
   String get importingLibraryName {
     String libraryName = _importingLibrary.getLibraryName();
     return libraryName == ""
       ? "<unnamed>"
       : libraryName;
   }
 
 }