Move common identifiers, names and selectors to a separate library.

pkg/compiler/lib/src/elements/common.dart

Index: pkg/compiler/lib/src/elements/common.dart
diff --git a/pkg/compiler/lib/src/elements/common.dart b/pkg/compiler/lib/src/elements/common.dart
index f9e2baa0af23b73169cbdce661fc907174a50cb8..e27317584b87fc14830a5f4727b48c11029bb85e 100644
--- a/pkg/compiler/lib/src/elements/common.dart
+++ b/pkg/compiler/lib/src/elements/common.dart
@@ -6,6 +6,8 @@
 
 library elements.common;
 
+import '../common/names.dart' show
+    Names;
 import '../compiler.dart' show
     Compiler,
     isPrivateName;
@@ -433,8 +435,7 @@ abstract class ClassElementCommon implements ClassElement {
   }
 
   FunctionType get callType {
-    MemberSignature member =
-        lookupInterfaceMember(const PublicName(Compiler.CALL_OPERATOR_NAME));
+    MemberSignature member = lookupInterfaceMember(Names.call);
     return member != null && member.isMethod ? member.type : null;
   }
 }