Remove implicit conversions from scoped_refptr to T* in extensions code.

extensions/browser/api/usb/usb_api.cc

 // Copyright 2014 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 "extensions/browser/api/usb/usb_api.h"
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 676 matching lines @@
 bool UsbRequestAccessFunction::Prepare() {
   parameters_ = RequestAccess::Params::Create(*args_);
   EXTENSION_FUNCTION_VALIDATE(parameters_.get());
   return true;
 }
 
 void UsbRequestAccessFunction::AsyncWorkStart() {
 #if defined(OS_CHROMEOS)
   scoped_refptr<UsbDevice> device =
       GetDeviceOrCompleteWithError(parameters_->device);
-  if (!device)
+  if (!device.get())
     return;
 
   device->RequestUsbAccess(
       parameters_->interface_id,
       base::Bind(&UsbRequestAccessFunction::OnCompleted, this));
 #else
   SetResult(new base::FundamentalValue(false));
   CompleteWithError(kErrorNotSupported);
 #endif  // OS_CHROMEOS
 }
@@ skipping 508 matching lines @@
     SetResult(new base::FundamentalValue(false));
     CompleteWithError(kErrorResetDevice);
     return;
   }
 
   SetResult(new base::FundamentalValue(true));
   AsyncWorkCompleted();
 }
 
 }  // namespace extensions