Create new interface instead of ClosureClassMap for variable usage information that is not Element-…

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

Index: pkg/compiler/lib/src/inferrer/builder_kernel.dart
diff --git a/pkg/compiler/lib/src/inferrer/builder_kernel.dart b/pkg/compiler/lib/src/inferrer/builder_kernel.dart
index 1e2f9a69a1213a713666ce93937901742552ea0b..657c4b77ffdef9f26810bda55e74bce5b4082292 100644
--- a/pkg/compiler/lib/src/inferrer/builder_kernel.dart
+++ b/pkg/compiler/lib/src/inferrer/builder_kernel.dart
@@ -103,7 +103,7 @@ class KernelTypeGraphBuilder extends ir.Visitor<TypeInformation> {
     // be handled specially, in that we are computing their LUB at
     // each update, and reading them yields the type that was found in a
     // previous analysis of [outermostElement].
-    ClosureClassMap closureData = compiler.closureToClassMapper
+    ClosureRepresentationInfo closureData = compiler.closureToClassMapper
         .getClosureToClassMapping(resolvedAst.element);
     closureData.forEachCapturedVariable((variable, field) {
       locals.setCaptured(variable, field);