Merge CoreTypes and CoreClasses into CommonElements.

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

Index: pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
diff --git a/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart b/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
index ef9fbfac4d57507f11cfc535c68ff65eb4922f1a..f9773c43014d516c726b0cb87f3a13ee8422453a 100644
--- a/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
+++ b/pkg/compiler/lib/src/inferrer/inferrer_visitor.dart
@@ -891,7 +891,7 @@ abstract class InferrerVisitor<T, E extends MinimalInferrerEngine<T>>
     // TODO(kasperl): We should be able to tell that the type of a literal
     // symbol is always a non-null exact symbol implementation -- not just
     // any non-null subtype of the symbol interface.
-    return types.nonNullSubtype(closedWorld.coreClasses.symbolClass);
+    return types.nonNullSubtype(closedWorld.commonElements.symbolClass);
   }
 
   @override
@@ -1042,7 +1042,7 @@ abstract class InferrerVisitor<T, E extends MinimalInferrerEngine<T>>
           }
         } else {
           // Narrow the elements to a non-null type.
-          DartType objectType = closedWorld.coreTypes.objectType;
+          DartType objectType = closedWorld.commonElements.objectType;
           if (Elements.isLocal(receiverElement)) {
             narrow(receiverElement, objectType, node);
           }