Media gallery fixups for scoped_refptr<T> operator T* removal.

chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac.mm

 // 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/media_galleries/mac/mtp_device_delegate_impl_mac.h"
 
 #include <algorithm>
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/threading/sequenced_worker_pool.h"
@@ skipping 183 matching lines @@
                  device_file_path, local_path,
                  success_callback, error_callback));
 }
 
 bool MTPDeviceDelegateImplMac::IsStreaming() {
   return false;
 }
 
 void MTPDeviceDelegateImplMac::ReadBytes(
     const base::FilePath& device_file_path,
-    net::IOBuffer* buf, int64 offset, int buf_len,
+    const scoped_refptr<net::IOBuffer>& buf,
+    int64 offset,
+    int buf_len,
     const ReadBytesSuccessCallback& success_callback,
     const ErrorCallback& error_callback) {
   NOTREACHED();
 }
 
 void MTPDeviceDelegateImplMac::CancelPendingTasksAndDeleteDelegate() {
   content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
       base::Bind(&MTPDeviceDelegateImplMac::CancelAndDelete,
                  base::Unretained(this)));
 }
@@ skipping 267 matching lines @@
   std::string device_name = base::FilePath(device_location).BaseName().value();
   std::string device_id;
   storage_monitor::StorageInfo::Type type;
   bool cracked = storage_monitor::StorageInfo::CrackDeviceId(
       device_name, &type, &device_id);
   DCHECK(cracked);
   DCHECK_EQ(storage_monitor::StorageInfo::MAC_IMAGE_CAPTURE, type);
 
   cb.Run(new MTPDeviceDelegateImplMac(device_id, device_location));
 }