Store constant variable initializers in elements.

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

Index: pkg/compiler/lib/src/inferrer/simple_types_inferrer.dart
diff --git a/pkg/compiler/lib/src/inferrer/simple_types_inferrer.dart b/pkg/compiler/lib/src/inferrer/simple_types_inferrer.dart
index b148b11e8cff04ce64fd0459246c439f89cebb9c..d13b1241f712c8c9056576141c06ec8234573f03 100644
--- a/pkg/compiler/lib/src/inferrer/simple_types_inferrer.dart
+++ b/pkg/compiler/lib/src/inferrer/simple_types_inferrer.dart
@@ -1299,8 +1299,9 @@ class SimpleTypeInferrerVisitor<T>
         element.isField &&
         Elements.isStaticOrTopLevelField(element) &&
         compiler.world.fieldNeverChanges(element)) {
+      FieldElement fieldElement = element;
       ConstantValue value =
-          compiler.backend.constants.getConstantValueForVariable(element);
+          compiler.backend.constants.getConstantValue(fieldElement.constant);
       if (value != null && value.isInt) {
         IntConstantValue intValue = value;
         return intValue.primitiveValue;