Adds imageWriterPrivate support for Windows

chrome/browser/extensions/api/image_writer_private/write_from_file_operation.cc

 // Copyright 2013 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 "base/file_util.h"
 #include "chrome/browser/extensions/api/image_writer_private/error_messages.h"
 #include "chrome/browser/extensions/api/image_writer_private/write_from_file_operation.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace extensions {
 namespace image_writer {
 
 using content::BrowserThread;
 
 WriteFromFileOperation::WriteFromFileOperation(
     base::WeakPtr<OperationManager> manager,
     const ExtensionId& extension_id,
     const base::FilePath& path,
     const std::string& storage_unit_id)
   : Operation(manager, extension_id, storage_unit_id) {
     image_path_ = path;
 }
 
 WriteFromFileOperation::~WriteFromFileOperation() {
 }
 
 void WriteFromFileOperation::Start() {
-  DVLOG(1) << "Starting file-to-usb write of " << image_path_.value()
-           << " to " << storage_unit_id_;
-
   if (!base::PathExists(image_path_) || base::DirectoryExists(image_path_)) {
     Error(error::kImageInvalid);
     return;
   }
 
-  WriteStart();
+  BrowserThread::PostTask(
+      BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&WriteFromFileOperation::WriteStart, this));
 }
 
 }  // namespace image_writer
 }  // namespace extensions