Significantly cleans up the ImageWriter Operation class and subclasses.

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;
+    const base::FilePath& user_file_path,
+    const std::string& device_path)
+    : Operation(manager, extension_id, device_path) {
+  image_path_ = user_file_path;
 }
 
-WriteFromFileOperation::~WriteFromFileOperation() {
-}
+WriteFromFileOperation::~WriteFromFileOperation() {}
 
-void WriteFromFileOperation::Start() {
-  DVLOG(1) << "Starting file-to-usb write of " << image_path_.value()
-           << " to " << storage_unit_id_;
-
+void WriteFromFileOperation::StartImpl() {
   if (!base::PathExists(image_path_) || base::DirectoryExists(image_path_)) {
+    DLOG(ERROR) << "Source must exist and not be a directory.";
     Error(error::kImageInvalid);
     return;
   }
 
-  WriteStart();
+  Unzip(base::Bind(
+      &WriteFromFileOperation::Write,
+      this,
+      base::Bind(&WriteFromFileOperation::VerifyWrite,
+                 this,
+                 base::Bind(&WriteFromFileOperation::Finish, this))));
 }
 
 }  // namespace image_writer
 }  // namespace extensions