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

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

Index: pkg/compiler/lib/src/inferrer/node_tracer.dart
diff --git a/pkg/compiler/lib/src/inferrer/node_tracer.dart b/pkg/compiler/lib/src/inferrer/node_tracer.dart
index 4bd3b4cc877bdb7a89dff8539e2ccef7ef19d006..1dda7d461ac5f40d27088ba8dc8720d8bc061d8c 100644
--- a/pkg/compiler/lib/src/inferrer/node_tracer.dart
+++ b/pkg/compiler/lib/src/inferrer/node_tracer.dart
@@ -355,7 +355,7 @@ abstract class TracerVisitor<T extends TypeInformation>
     /// return false. Instead we catch that case here for now.
     // TODO(herhut): Handle creation of closures from instances of Function.
     if (element.isInstanceMember &&
-        element.name == Compiler.CALL_OPERATOR_NAME) {
+        element.name == Identifiers.call) {
       return true;
     }
     Element outermost = element.outermostEnclosingMemberOrTopLevel;