Validation of extension api callback and event parameters in DEBUG

chrome/renderer/extensions/extension_process_bindings.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/extensions/extension_process_bindings.h"
 
 #include "base/singleton.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
@@ skipping 280 matching lines @@
   if (request == pending_requests.end())
     return;  // The frame went away.
 
   v8::HandleScope handle_scope;
   v8::Handle<v8::Value> argv[5];
   argv[0] = v8::Integer::New(request_id);
   argv[1] = v8::String::New(request->second->name.c_str());
   argv[2] = v8::Boolean::New(success);
   argv[3] = v8::String::New(response.c_str());
   argv[4] = v8::String::New(error.c_str());
-  bindings_utils::CallFunctionInContext(
+  v8::Handle<v8::Value> retval = bindings_utils::CallFunctionInContext(
       request->second->context, "handleResponse", arraysize(argv), argv);
+  // In debug, the js will validate the callback parameters and return a 
+  // string if a validation error has occured.
+#ifdef _DEBUG
+  if (!retval.IsEmpty() && !retval->IsUndefined()) {
+    std::string error = *v8::String::AsciiValue(retval);
+    DCHECK(false) << error;
+  }
+#endif
 
   pending_requests.erase(request);
 }
 
 // static
 void ExtensionProcessBindings::SetPageActions(
     const std::string& extension_id,
     const std::vector<std::string>& page_actions) {
   PageActionIdMap& page_action_map = *GetPageActionMap();
   if (!page_actions.empty()) {
@@ skipping 68 matching lines @@
 
   v8::Local<v8::Function> function =
       v8::Local<v8::Function>::Cast(console_error);
   v8::Local<v8::Value> argv[] = { v8::String::New(error_msg.c_str()) };
   if (!function.IsEmpty())
     function->Call(console->ToObject(), arraysize(argv), argv);
 
   return v8::Undefined();
 #endif
 }