Move dart2jslib parts into separate libraries.

pkg/compiler/lib/src/deferred_load.dart

Index: pkg/compiler/lib/src/deferred_load.dart
diff --git a/pkg/compiler/lib/src/deferred_load.dart b/pkg/compiler/lib/src/deferred_load.dart
index 3ae1bae52e7094fa72a9620929864ec4de9a14c8..6b808763652fb57ceb6cf503071b1f419d4c20de 100644
--- a/pkg/compiler/lib/src/deferred_load.dart
+++ b/pkg/compiler/lib/src/deferred_load.dart
@@ -9,17 +9,12 @@ import 'constants/values.dart' show
     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,
@@ -34,16 +29,13 @@ import 'elements/elements.dart' show
     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,
@@ -52,12 +44,11 @@ import 'tree/tree.dart' show
     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.