DO NOT MERGE ANYWHERE Use synchronous writes when setting up BCB.

Commit [1] made similar changes into AOSP code, but it requires multiple
CLs to cherry-pick into cw-e branch. So we make a separate CL to fix the
issue.

[1] commit bd82b27341336f0b375c3bc2a7bf48b2ccc20c1f

Bug: 27247370
Change-Id: Id5c08a6a29284353f891cdbaa224feee891f3807
1 file changed