Move dart2jslib parts into separate libraries.

pkg/compiler/lib/src/compile_time_constants.dart

Index: pkg/compiler/lib/src/compile_time_constants.dart
diff --git a/pkg/compiler/lib/src/compile_time_constants.dart b/pkg/compiler/lib/src/compile_time_constants.dart
index 063653733088cc706e018863d7b6e861bb3f5597..f6974ca6e982695a4636d271e812d6c51cf7abe7 100644
--- a/pkg/compiler/lib/src/compile_time_constants.dart
+++ b/pkg/compiler/lib/src/compile_time_constants.dart
@@ -10,9 +10,15 @@ import 'constants/evaluation.dart';
 import 'constants/expressions.dart';
 import 'constants/values.dart';
 import 'dart_types.dart';
-import 'dart2jslib.dart' show Compiler, CompilerTask, MessageKind, WorldImpact, invariant;
+import 'dart2jslib.dart' show
+    Compiler,
+    CompilerTask,
+    invariant;
+import 'enqueue.dart' show
+    WorldImpact;
 import 'elements/elements.dart';
 import 'elements/modelx.dart' show FunctionElementX;
+import 'messages.dart' show MessageKind;
 import 'resolution/resolution.dart';
 import 'resolution/operators.dart';
 import 'tree/tree.dart';
@@ -1366,4 +1372,4 @@ class _CompilerEnvironment implements Environment {
   String readFromEnvironment(String name) {
     return compiler.fromEnvironment(name);
   }
-}
+}