am 78f0f8cb: Merge changes 3953,3954 into donut

Merge commit '78f0f8cb2efe9410127c39201e240f6d438eb53c'

* commit '78f0f8cb2efe9410127c39201e240f6d438eb53c':
  Make the file backup helper not crash if a file you requested
  Fix SharedPrefsBackupHelper so it doesn't hard code the paths to the files.