Implement .getCallType

pkg/compiler/lib/src/kernel/types.dart

Index: pkg/compiler/lib/src/kernel/types.dart
diff --git a/pkg/compiler/lib/src/kernel/types.dart b/pkg/compiler/lib/src/kernel/types.dart
index 14fd6049fd9b389729f0499365cea5b57d17bfb8..8a46be3364f0e9bf3b1ce68d54b699ee6df54bcf 100644
--- a/pkg/compiler/lib/src/kernel/types.dart
+++ b/pkg/compiler/lib/src/kernel/types.dart
@@ -62,8 +62,8 @@ class _KernelDartTypes extends DartTypes {
 
   @override
   FunctionType getCallType(InterfaceType type) {
-    // TODO(redemption): Compute the call type.
-    return null;
+    DartType callType = elementMap._getCallType(type);
+    return callType is FunctionType ? callType : null;
   }
 
   @override
@@ -119,7 +119,7 @@ abstract class _AbstractTypeRelationMixin
   @override
   FunctionType getCallType(InterfaceType type) {
     // TODO(redemption): Compute the call type.
-    return null;
+    return elementMap._getCallType(type);
   }
 
   @override