Move dart2jslib parts into separate libraries.

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/values.dart' show
     ConstantValue,
     ConstructedConstantValue,
     DeferredConstantValue,
     StringConstantValue;
-
 import 'dart2jslib.dart' show
     Backend,
     Compiler,
     CompilerTask,
-    invariant,
-    MessageKind;
-
-import 'js_backend/js_backend.dart' show
-    JavaScriptBackend;
-
+    invariant;
+import 'dart_types.dart';
 import 'elements/elements.dart' show
     AccessorElement,
     AstElement,
     ClassElement,
     Element,
     ElementKind,
     Elements,
     FunctionElement,
     LibraryElement,
     MetadataAnnotation,
     PrefixElement,
     ScopeContainerElement,
     TypedefElement,
     VoidElement;
-
-import 'dart_types.dart';
-
-import 'util/util.dart' show
-    Link, makeUnique;
-import 'util/uri_extras.dart' as uri_extras;
-
-import 'util/setlet.dart' show
-    Setlet;
-
+import 'js_backend/js_backend.dart' show
+    JavaScriptBackend;
+import 'messages.dart' show MessageKind;
+import 'resolution/resolution.dart' show
+    AnalyzableElementX,
+    TreeElements;
+import 'tree/tree.dart' as ast;
 import 'tree/tree.dart' show
     Import,
     LibraryTag,
     LibraryDependency,
     LiteralDartString,
     LiteralString,
     NewExpression,
     Node;
-
-import 'tree/tree.dart' as ast;
-
-import 'resolution/resolution.dart' show
-    AnalyzableElementX,
-    TreeElements;
+import 'util/setlet.dart' show
+    Setlet;
+import 'util/uri_extras.dart' as uri_extras;
+import 'util/util.dart' show
+    Link, makeUnique;
 
 /// A "hunk" of the program that will be loaded whenever one of its [imports]
 /// are loaded.
 ///
 /// Elements that are only used in one deferred import, is in an OutputUnit with
 /// the deferred import as single element in the [imports] set.
 ///
 /// Whenever a deferred Element is shared between several deferred imports it is
 /// in an output unit with those imports in the [imports] Set.
 ///
@@ skipping 819 matching lines @@
         _importingLibrary = importingLibrary;
 
   String get importingLibraryName {
     String libraryName = _importingLibrary.getLibraryName();
     return libraryName == ""
       ? "<unnamed>"
       : libraryName;
   }
 
 }