[fsp] Pass more detailed errors to the providing extension.

chrome/browser/chromeos/file_system_provider/service.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_SERVICE_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 64 matching lines @@
       const FileSystemFactoryCallback& factory_callback);
 
   // Sets a custom Registry implementation. Used by unit tests.
   void SetRegistryForTesting(scoped_ptr<RegistryInterface> registry);
 
   // Mounts a file system provided by an extension with the |extension_id|. If
   // |writable| is set to true, then the file system is mounted in a R/W mode.
   // Otherwise, only read-only operations are supported. If change notification
   // tags are supported, then |supports_notify_tag| must be true. Note, that
   // it is required in order to enable the internal cache. For success, returns
-  // true, otherwise false.
-  bool MountFileSystem(const std::string& extension_id,
-                       const MountOptions& options);
+  // base::File::FILE_OK, otherwise an error code.
+  base::File::Error MountFileSystem(const std::string& extension_id,
+                                    const MountOptions& options);
 
   // Unmounts a file system with the specified |file_system_id| for the
-  // |extension_id|. For success returns true, otherwise false.
-  bool UnmountFileSystem(const std::string& extension_id,
-                         const std::string& file_system_id,
-                         UnmountReason reason);
+  // |extension_id|. For success returns base::File::FILE_OK, otherwise an error
+  // code.
+  base::File::Error UnmountFileSystem(const std::string& extension_id,
+                                      const std::string& file_system_id,
+                                      UnmountReason reason);
 
   // Requests unmounting of the file system. The callback is called when the
   // request is accepted or rejected, with an error code. Returns false if the
   // request could not been created, true otherwise.
   bool RequestUnmount(const std::string& extension_id,
                       const std::string& file_system_id);
 
   // Returns a list of information of all currently provided file systems. All
   // items are copied.
   std::vector<ProvidedFileSystemInfo> GetProvidedFileSystemInfoList();
@@ skipping 79 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<Service> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(Service);
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_H_