clean up SmbFileSystem member variables

This change includes some cleanup, removing unused member variables and
removing a reference to a bug that has been fixed.

Bug: chromium:757625, chromium:796334
Change-Id: I6a5901f355050a47aeb59850e34ed463b79b6899
Reviewed-on: https://chromium-review.googlesource.com/978379Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545494}

chrome/browser/chromeos/smb_client/smb_file_system.cc

@@ -411,8 +411,7 @@ AbortCallback SmbFileSystem::AddWatcher(
     const storage::WatcherManager::NotificationCallback&
         notification_callback) {
   // Watchers are not supported.
-  // This method should not be getting called since watchable is set to false.
-  // crbug.com/796334.
+  NOTIMPLEMENTED();
   callback.Run(base::File::FILE_ERROR_INVALID_OPERATION);
   return CreateAbortCallback();
 }
@@ -423,8 +422,7 @@ void SmbFileSystem::RemoveWatcher(
     bool recursive,
     const storage::AsyncFileUtil::StatusCallback& callback) {
   // Watchers are not supported.
-  // This method should not be getting called since watchable is set to false.
-  // http://www.crbug.com/796334.
+  NOTIMPLEMENTED();
   callback.Run(base::File::FILE_ERROR_INVALID_OPERATION);
 }
 
@@ -440,9 +438,8 @@ file_system_provider::RequestManager* SmbFileSystem::GetRequestManager() {
 
 file_system_provider::Watchers* SmbFileSystem::GetWatchers() {
   // Watchers are not supported.
-  // This method should not be getting called since watchable is set to false.
-  // http://www.crbug.com/796334.
-  return &watchers_;
+  NOTIMPLEMENTED();
+  return nullptr;
 }
 
 const file_system_provider::OpenedFiles& SmbFileSystem::GetOpenedFiles() const {

chrome/browser/chromeos/smb_client/smb_file_system.h

@@ -246,10 +246,9 @@ class SmbFileSystem : public file_system_provider::ProvidedFileSystemInterface,
   // the OperationId for the newly created Operation.
   OperationId EnqueueTaskAndGetOperationId(SmbTask task);
 
-  file_system_provider::ProvidedFileSystemInfo file_system_info_;
-  file_system_provider::OpenedFiles opened_files_;
-  storage::AsyncFileUtil::EntryList entry_list_;
-  file_system_provider::Watchers watchers_;
+  const file_system_provider::ProvidedFileSystemInfo file_system_info_;
+  // opened_files_ is marked const since is currently unsupported.
+  const file_system_provider::OpenedFiles opened_files_;
 
   UnmountCallback unmount_callback_;
   TempFileManager temp_file_manager_;