Adding tests for USB extension API

chrome/browser/usb/usb_device.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/usb/usb_device.h"
 
 #include "base/stl_util.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/usb/usb_service.h"
 #include "third_party/libusb/libusb.h"
@@ skipping 81 matching lines @@
 
 UsbDevice::Transfer::Transfer() {}
 
 UsbDevice::Transfer::~Transfer() {}
 
 UsbDevice::UsbDevice(UsbService* service, PlatformUsbDeviceHandle handle)
     : service_(service), handle_(handle) {
   DCHECK(handle) << "Cannot create device with NULL handle.";
 }
 
+UsbDevice::UsbDevice() : service_(NULL), handle_(NULL) {}
+
 UsbDevice::~UsbDevice() {}
 
 void UsbDevice::Close() {
   CheckDevice();
   service_->CloseDevice(this);
   handle_ = NULL;
 }
 
 void UsbDevice::TransferComplete(PlatformUsbTransferHandle handle) {
   base::AutoLock lock(lock_);
@@ skipping 88 matching lines @@
 
   Transfer transfer;
   transfer.buffer = buffer;
   transfer.callback = callback;
 
   {
     base::AutoLock lock(lock_);
     transfers_[handle] = transfer;
   }
 }