[fsp] Add support for truncating files.

chrome/browser/chromeos/file_system_provider/operations/truncate.h

 // 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.
 
-#ifndef CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OPERATIONS_CREATE_FILE_H_
-#define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OPERATIONS_CREATE_FILE_H_
+#ifndef CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OPERATIONS_TRUNCATE_H_
+#define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OPERATIONS_TRUNCATE_H_
 
 #include "base/files/file.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/chromeos/file_system_provider/operations/operation.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_info.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_interface.h"
 #include "chrome/browser/chromeos/file_system_provider/request_value.h"
 #include "webkit/browser/fileapi/async_file_util.h"
 
 namespace base {
 class FilePath;
 }  // namespace base
 
 namespace extensions {
 class EventRouter;
 }  // namespace extensions
 
 namespace chromeos {
 namespace file_system_provider {
 namespace operations {
 
 // Creates a file. If the file already exists, then the operation will fail with
 // the FILE_ERROR_EXISTS error. Created per request.
-class CreateFile : public Operation {
+class Truncate : public Operation {
  public:
-  CreateFile(extensions::EventRouter* event_router,
-             const ProvidedFileSystemInfo& file_system_info,
-             const base::FilePath& file_path,
-             const fileapi::AsyncFileUtil::StatusCallback& callback);
-  virtual ~CreateFile();
+  Truncate(extensions::EventRouter* event_router,
+           const ProvidedFileSystemInfo& file_system_info,
+           const base::FilePath& file_path,
+           int64 length,
+           const fileapi::AsyncFileUtil::StatusCallback& callback);
+  virtual ~Truncate();
 
   // Operation overrides.
   virtual bool Execute(int request_id) OVERRIDE;
   virtual void OnSuccess(int request_id,
                          scoped_ptr<RequestValue> result,
                          bool has_more) OVERRIDE;
   virtual void OnError(int request_id,
                        scoped_ptr<RequestValue> result,
                        base::File::Error error) OVERRIDE;
 
  private:
   base::FilePath file_path_;
+  int64 length_;
   const fileapi::AsyncFileUtil::StatusCallback callback_;
 
-  DISALLOW_COPY_AND_ASSIGN(CreateFile);
+  DISALLOW_COPY_AND_ASSIGN(Truncate);
 };
 
 }  // namespace operations
 }  // namespace file_system_provider
 }  // namespace chromeos
 
-#endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OPERATIONS_CREATE_FILE_H_
+#endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_OPERATIONS_TRUNCATE_H_