am 3d84280c: Merge "File writer has a designated writer thread now" into gingerbread

Merge commit '3d84280ccc31d12765e2efe03e2dd3ade1acfc33' into gingerbread-plus-aosp

* commit '3d84280ccc31d12765e2efe03e2dd3ade1acfc33':
  File writer has a designated writer thread now