Move computeType to TypedElement and TypeDeclarationElement.

pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart

Index: pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart b/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
index 6f294f6c00a35469da2d78e6c0d798674610f035..29a460673b4f8e2560ec5b6fb995a4cbcfd7be96 100644
--- a/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
@@ -213,6 +213,7 @@ class RuntimeTypeGenerator {
         call = cls.lookupBackendMember(Compiler.CALL_OPERATOR_NAME);
       }
       if (call != null && call.isFunction) {
+        FunctionElement callFunction = call;
         // A superclass might already implement the Function interface. In such
         // a case, we can avoid emiting the is test here.
         if (!cls.superclass.implementsFunction(compiler)) {
@@ -221,8 +222,8 @@ class RuntimeTypeGenerator {
                                     generateSubstitution,
                                     generated);
         }
-        FunctionType callType = call.computeType(compiler);
-        generateFunctionTypeSignature(call, callType);
+        FunctionType callType = callFunction.computeType(compiler);
+        generateFunctionTypeSignature(callFunction, callType);
       }
     }