Bug fixes for hot reload

runtime/vm/isolate_reload_test.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
@@ skipping 210 matching lines @@
       "main() {\n"
       "  new Foo();\n"
       "  return 44;\n"
       "}\n";
 
   lib = TestCase::ReloadTestScript(kReloadScript);
   EXPECT_ERROR(lib, "Number of instance fields changed");
 }
 
 
+TEST_CASE(IsolateReload_ClassFieldAdded2) {
+  const char* kScript =
+      "class Foo {\n"
+      "  var x;\n"
+      "  var y;\n"
+      "}\n"
+      "main() {\n"
+      "  new Foo();\n"
+      "  return 44;\n"
+      "}\n";
+
+  Dart_Handle lib = TestCase::LoadTestScript(kScript, NULL);
+  EXPECT_VALID(lib);
+
+  EXPECT_EQ(44, SimpleInvoke(lib, "main"));
+
+  const char* kReloadScript =
+      "class Foo {\n"
+      "  var x;\n"
+      "  var y;\n"
+      "  var z;\n"
+      "}\n"
+      "main() {\n"
+      "  new Foo();\n"
+      "  return 44;\n"
+      "}\n";
+
+  lib = TestCase::ReloadTestScript(kReloadScript);
+  EXPECT_ERROR(lib, "Number of instance fields changed");
+}
+
+
 TEST_CASE(IsolateReload_ClassFieldRemoved) {
   const char* kScript =
       "class Foo {\n"
       "  var x;\n"
       "  var y;\n"
       "}\n"
       "main() {\n"
       "  new Foo();\n"
       "  return 44;\n"
       "}\n";
@@ skipping 1582 matching lines @@
 
   // ...and the non-core subclass is still named AIterator.
   new_subclass = subclasses.At(subclasses.Length() - 1);
   name = Class::Cast(new_subclass).Name();
   EXPECT_STREQ("AIterator", name.ToCString());
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart