Add best-effort/allow rollback flags on WorkItem.

chrome/installer/util/copy_tree_work_item.h

 // Copyright (c) 2011 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_INSTALLER_UTIL_COPY_TREE_WORK_ITEM_H_
 #define CHROME_INSTALLER_UTIL_COPY_TREE_WORK_ITEM_H_
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/gtest_prod_util.h"
 #include "chrome/installer/util/work_item.h"
 
 // A WorkItem subclass that recursively copies a file system hierarchy from
 // source path to destination path. It also creates all necessary intermediate
 // paths of the destination path if they do not exist. The file system
 // hierarchy could be a single file, or a directory.
 // Under the cover CopyTreeWorkItem moves the destination path, if existing,
 // to the temporary directory passed in, and then copies the source hierarchy
 // to the destination location. During rollback the original destination
 // hierarchy is moved back.
 // NOTE: It is a best practice to ensure that the temporary directory is on the
 // same volume as the destination path.  If this is not the case, the existing
 // destination path is not moved, but rather copied, to the destination path.
 // This will result in in-use files being left behind, as well as potentially
 // losing ACLs or other metadata in the case of a rollback.
 class CopyTreeWorkItem : public WorkItem {
  public:
   ~CopyTreeWorkItem() override;
 
-  bool Do() override;
-
-  void Rollback() override;
-
  private:
   friend class WorkItem;
 
   // See comments on corresponding member variables for the semantics of
   // arguments.
   // Notes on temp_path: to facilitate rollback, the caller needs to supply
   // a temporary directory to save the original files if they exist under
   // dest_path.
   CopyTreeWorkItem(const base::FilePath& source_path,
                    const base::FilePath& dest_path,
                    const base::FilePath& temp_dir,
                    CopyOverWriteOption overwrite_option,
                    const base::FilePath& alternative_path);
 
+  // WorkItem:
+  bool DoImpl() override;
+  void RollbackImpl() override;
+
   // Checks if the path specified is in use (and hence can not be deleted)
   bool IsFileInUse(const base::FilePath& path);
 
   // Source path to copy files from.
   base::FilePath source_path_;
 
   // Destination path to copy files to.
   base::FilePath dest_path_;
 
   // Temporary directory that can be used.
@@ skipping 22 matching lines @@
   base::ScopedTempDir backup_path_;
 
   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileSameContent);
   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileInUse);
   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileAndCleanup);
   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, NewNameAndCopyTest);
   FRIEND_TEST_ALL_PREFIXES(CopyTreeWorkItemTest, CopyFileInUseAndCleanup);
 };
 
 #endif  // CHROME_INSTALLER_UTIL_COPY_TREE_WORK_ITEM_H_