Added support for multiple parameters to Extension API callbacks.

chrome/browser/extensions/api/usb/usb_api.cc

 // Copyright (c) 2012 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/browser/extensions/api/usb/usb_api.h"
 
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/extensions/api/api_resource_controller.h"
@@ skipping 28 matching lines @@
 }
 
 void UsbFindDeviceFunction::Work() {
   UsbService* const service =
       UsbServiceFactory::GetInstance()->GetForProfile(profile());
   DCHECK(service) << "No UsbService associated with profile.";
 
   UsbDevice* const device = service->FindDevice(parameters_->vendor_id,
                                                 parameters_->product_id);
   if (!device) {
-    result_.reset(base::Value::CreateNullValue());
+    SetResult(base::Value::CreateNullValue());
     return;
   }
 
   UsbDeviceResource* const resource = new UsbDeviceResource(event_notifier_,
                                                             device);
 
   Device result;
   result.handle = controller()->AddAPIResource(resource);
   result.vendor_id = parameters_->vendor_id;
   result.product_id = parameters_->product_id;
-  result_ = result.ToValue();
+  SetResult(FindDevice::Result::Create(result));
 }
 
 bool UsbFindDeviceFunction::Respond() {
   return true;
 }
 
 UsbCloseDeviceFunction::UsbCloseDeviceFunction() {}
 
 UsbCloseDeviceFunction::~UsbCloseDeviceFunction() {}
 
@@ skipping 93 matching lines @@
   if (device) {
     device->IsochronousTransfer(parameters_->transfer_info);
   }
 }
 
 bool UsbIsochronousTransferFunction::Respond() {
   return true;
 }
 
 }  // namespace extensions