Remove use of FunctionSignature et al from call_structure.dart

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

Index: pkg/compiler/lib/src/inferrer/closure_tracer.dart
diff --git a/pkg/compiler/lib/src/inferrer/closure_tracer.dart b/pkg/compiler/lib/src/inferrer/closure_tracer.dart
index 007d1c4fac9eedb2e7098a28185b112d79f406ad..0d0072219917e76b71d08dbbea232831a51c731e 100644
--- a/pkg/compiler/lib/src/inferrer/closure_tracer.dart
+++ b/pkg/compiler/lib/src/inferrer/closure_tracer.dart
@@ -53,8 +53,7 @@ class ClosureTracerVisitor extends TracerVisitor {
     Selector selector = info.selector;
     TypeMask mask = info.mask;
     tracedElements.forEach((FunctionElement functionElement) {
-      if (!selector.callStructure
-          .signatureApplies(functionElement.functionSignature)) {
+      if (!selector.callStructure.signatureApplies(functionElement.type)) {
         return;
       }
       inferrer.updateParameterAssignments(