[fsp] Add support for truncating files.

chrome/browser/chromeos/file_system_provider/request_manager.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_REQUEST_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_REQUEST_MANAGER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 17 matching lines @@
   GET_METADATA,
   READ_DIRECTORY,
   OPEN_FILE,
   CLOSE_FILE,
   READ_FILE,
   CREATE_DIRECTORY,
   DELETE_ENTRY,
   CREATE_FILE,
   COPY_ENTRY,
   MOVE_ENTRY,
+  TRUNCATE,
   TESTING
 };
 
 // Converts a request type to human-readable format.
 std::string RequestTypeToString(RequestType type);
 
 // Manages requests between the service, async utils and the providing
 // extensions.
 class RequestManager {
  public:
@@ skipping 122 matching lines @@
   base::WeakPtrFactory<RequestManager> weak_ptr_factory_;
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestManager);
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_REQUEST_MANAGER_H_