chromeos: Use WriteBatch to update DriveResourceMetadata DB

chrome/browser/chromeos/drive/drive_resource_metadata.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_DRIVE_RESOURCE_METADATA_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_RESOURCE_METADATA_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 326 matching lines @@
   base::FilePath GetFilePath(const std::string& resource_id);
 
   // Recursively extracts the paths set of all sub-directories.
   void GetDescendantDirectoryPaths(const std::string& resource_id,
                                    std::set<base::FilePath>* child_directories);
 
   // Adds a child entry to its parent directory.
   // The method will also do name de-duplication to ensure that the
   // exposed presentation path does not have naming conflicts. Two files with
   // the same name "Foo" will be renames to "Foo (1)" and "Foo (2)".
-  void AddEntryToDirectory(const DriveEntryProto& entry);
+  bool AddEntryToDirectory(const DriveEntryProto& entry);
 
-  // Removes the entry from its parent directory.
-  void RemoveDirectoryChild(const std::string& child_resource_id);
-
-  // Detaches the entry from its parent directory.
-  void DetachEntryFromDirectory(const std::string& child_resource_id);
-
-  // Removes child elements of directory.
-  void RemoveDirectoryChildren(const std::string& directory_resource_id);
+  // Removes the entry and its descendants.
+  bool RemoveEntryRecursively(const std::string& resource_id);
 
   // Converts the children as a vector of DriveEntryProto.
   scoped_ptr<DriveEntryProtoVector> DirectoryChildrenToProtoVector(
       const std::string& directory_resource_id);
 
   const base::FilePath data_directory_path_;
 
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
 
   scoped_ptr<DriveResourceMetadataStorage> storage_;
 
   // This should remain the last member so it'll be destroyed first and
   // invalidate its weak pointers before other members are destroyed.
   base::WeakPtrFactory<DriveResourceMetadata> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DriveResourceMetadata);
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_RESOURCE_METADATA_H_