am b1104b37: Merge "Make SharedPreferencesBackupHelper wait for async SharedPreference writes" into gingerbread

Merge commit 'b1104b3713febb75164938a465c3022e1879245f' into gingerbread-plus-aosp

* commit 'b1104b3713febb75164938a465c3022e1879245f':
  Make SharedPreferencesBackupHelper wait for async SharedPreference writes