Move dart2jslib parts into separate libraries.

site/try/poi/poi.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 trydart.poi;
 
 import 'dart:async' show
     Completer,
     Future;
 
@@ skipping 11 matching lines @@
     LibraryUpdater;
 
 import 'package:compiler/src/source_file_provider.dart' show
     FormattingDiagnosticHandler;
 
 import 'package:compiler/compiler.dart' as api;
 
 import 'package:compiler/src/dart2jslib.dart' show
     Compiler,
     CompilerTask,
-    Enqueuer,
     QueueFilter,
     WorkItem;
 
 import 'package:compiler/src/elements/visitor.dart' show
     BaseElementVisitor;
 
 import 'package:compiler/src/elements/elements.dart' show
     AbstractFieldElement,
     ClassElement,
     CompilationUnitElement,
     Element,
     ElementCategory,
     FunctionElement,
     LibraryElement,
     ScopeContainerElement;
 
 import 'package:compiler/src/elements/modelx.dart' as modelx;
 
 import 'package:compiler/src/elements/modelx.dart' show
     DeclarationSite;
 
+import 'package:compiler/src/enqueue.dart' show
+    Enqueuer;
+
 import 'package:compiler/src/dart_types.dart' show
     DartType;
 
 import 'package:compiler/src/scanner/scannerlib.dart' show
     EOF_TOKEN,
     IDENTIFIER_TOKEN,
     KEYWORD_TOKEN,
     PartialClassElement,
     PartialElement,
     Token;
@@ skipping 489 matching lines @@
     f(work);
     printWallClock('Processed ${work.element}.');
   }
 }
 
 class PoiTask extends CompilerTask {
   PoiTask(Compiler compiler) : super(compiler);
 
   String get name => 'POI';
 }