Remove computeMask from ConstantValue.

pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart

Index: pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
diff --git a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
index ae3427a55e791a355daa0ad0478488cb874ccdeb..3b075ba4c41dc3345388c460f6d0325e7e6772f6 100644
--- a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
+++ b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
@@ -35,6 +35,8 @@ import '../types/types.dart'
          TypeMask,
          TypesInferrer,
          ValueTypeMask;
+import '../types/constants.dart'
+    show COMPUTE_TYPE_MASK;
 import '../universe/universe.dart'
     show Selector,
          SideEffects,
@@ -807,7 +809,8 @@ class TypeGraphInferrerEngine
                 // Although we might find a better type, we have to keep
                 // the old type around to ensure that we get a complete view
                 // of the type graph and do not drop any flow edges.
-                TypeMask refinedType = value.computeMask(compiler);
+                TypeMask refinedType =
+                    value.accept(COMPUTE_TYPE_MASK, compiler);
                 assert(TypeMask.assertIsNormalized(refinedType, classWorld));
                 type = new NarrowTypeInformation(type, refinedType);
                 types.allocatedTypes.add(type);