Summary:
For VerifyBackup(), backup files can be spread across "shared/",
"shared_checksum/", and "private/" subdirectories, so we have to
bulk get all three.
For CreateNewBackup(), we make two separate bulk calls: one for the
data files and one for WAL files.
There is also a new helper function, ExtendPathnameToSizeBytes(),
that translates the file attributes vector to a map. I decided to leave
GetChildrenFileAttributes()'s (from D53781) return type as vector to
keep it consistent with GetChildren().
Depends on D53781.
Test Plan:
verified relevant unit tests
$ ./backupable_db_test
Reviewers: IslamAbdelRahman, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D53919
f8e90e8753