Recovery may be used to recover files with I/O errors, which would not
interact well with memory-mapped I/O.
[AFAICT, SQLite doesn't use memory-mapped I/O on temporary files, but as
of yet I don't see why this might be.]
BUG=551110
Review URL: https://codereview.chromium.org/1414563010
Cr-Commit-Position: refs/heads/master@{#358083}
2f3a814be0