Propagate types of static const variables.

pkg/compiler/lib/src/js_backend/codegen/task.dart

Index: pkg/compiler/lib/src/js_backend/codegen/task.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/task.dart b/pkg/compiler/lib/src/js_backend/codegen/task.dart
index 870bba8b3c5157dba1aeb3cd7583c7f459743e2a..cad67af3c8e528e146e92a00d64e309e8dd32a70 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/task.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/task.dart
@@ -201,8 +201,6 @@ class CpsFunctionCompiler implements FunctionCompiler {
 
   cps.FunctionDefinition optimizeCpsIr(cps.FunctionDefinition cpsFunction) {
     cpsOptimizationTask.measure(() {
-      TypeMaskSystem typeSystem = new TypeMaskSystem(compiler);
-
       applyCpsPass(new RedundantJoinEliminator(), cpsFunction);
       applyCpsPass(new RedundantPhiEliminator(), cpsFunction);
       applyCpsPass(new InsertRefinements(typeSystem), cpsFunction);