Fix ChangeListLoader's callback invocation.

chrome/browser/chromeos/drive/change_list_loader.h

 // Copyright (c) 2012 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_DRIVE_CHANGE_LIST_LOADER_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_CHANGE_LIST_LOADER_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 134 matching lines @@
 
   // Part of LoadDirectoryFromServer(). Called when
   // DriveScheduler::GetAboutResource() is complete. Calls
   // DoLoadDirectoryFromServer() to initiate the directory contents loading.
   void LoadDirectoryFromServerAfterGetAbout(
       const std::string& directory_resource_id,
       const FileOperationCallback& callback,
       google_apis::GDataErrorCode status,
       scoped_ptr<google_apis::AboutResource> about_resource);
 
-  // Initiates the directory contents loading, based on
-  // |directory_fetch_info|.
+  // Initiates the directory contents loading, based on |directory_fetch_info|.
+  // When it is finished it just runs |callback| but no other callbacks in
+  // |pending_load_callback_|, because it depends on the caller whether to flush
+  // callbacks. Thus, the caller must be responsible for task flushing.
   void DoLoadDirectoryFromServer(const DirectoryFetchInfo& directory_fetch_info,
                                  const FileOperationCallback& callback);
 
   // Part of DoLoadDirectoryFromServer(). Called after
   // LoadFromServer() is complete.
   void DoLoadDirectoryFromServerAfterLoad(
       const DirectoryFetchInfo& directory_fetch_info,
       const FileOperationCallback& callback,
       const ScopedVector<google_apis::ResourceList>& resource_list,
       DriveFileError error);
@@ skipping 121 matching lines @@
 
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<ChangeListLoader> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(ChangeListLoader);
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_CHANGE_LIST_LOADER_H_