Rework service extensions to be safe

runtime/vm/service.cc

 // Copyright (c) 2013, 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 "vm/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 887 matching lines @@
   ASSERT(!developer_lib.IsNull());
   const Function& schedule_extension = Function::Handle(
       developer_lib.LookupLocalFunction(Symbols::_scheduleExtension()));
   ASSERT(!schedule_extension.IsNull());
   const Array& arguments = Array::Handle(Array::New(5));
   arguments.SetAt(0, method_name);
   arguments.SetAt(1, parameter_keys);
   arguments.SetAt(2, parameter_values);
   arguments.SetAt(3, reply_port);
   arguments.SetAt(4, id);
-  return (DartEntry::InvokeFunction(schedule_extension, arguments) ==
-          Object::bool_true().raw());
+  const Object& result = Object::Handle(
+      DartEntry::InvokeFunction(schedule_extension, arguments));
+  if (result.IsNull()) {
+    return false;
+  }
+  Isolate* isolate = Isolate::Current();
+  isolate->AppendExtensionCall(Instance::Cast(result));
+  return true;
 }
 
 
 static const MethodParameter* get_isolate_params[] = {
   ISOLATE_PARAMETER,
   NULL,
 };
 
 
 static bool GetIsolate(Isolate* isolate, JSONStream* js) {
@@ skipping 2214 matching lines @@
     ServiceMethodDescriptor& method = service_methods_[i];
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 
 }  // namespace dart