[merge m-65]: macOS V2 Sandbox: Send profile to child process robustly.

This is CL squashes three cherry-picks into one CL for the purpose of
merging to m-65. The CLs make IPC of the seatbelt profile from the
browser to the child process robust by adding logging and handling short
writes or temporarily busy file descriptors.

Original CLs:
78e7405af0e16c10500bc5b923e938ad9f52e735
macOS V2 Sandbox: Add logging to failures in profile communication.
Change-Id: I425bedc92d47a27f90b4d80541d2cbf68e8f6a21
Reviewed-on: https://chromium-review.googlesource.com/916946
Cr-Commit-Position: refs/heads/master@{#536495}

7ea6cf78e3bced2f48c49394493832520cdc97f0
macOS V2 Sandbox: Send serialized seatbelt profile in a loop.
Change-Id: Ib1f4c57c61d3ce68b875b347de480f514100d3c2
Reviewed-on: https://chromium-review.googlesource.com/920765
Cr-Commit-Position: refs/heads/master@{#537360}

fb63be6d346dbbbe47e3edf3a7e8e6b6b7f286d7
macOS V2 Sandbox: Continue sending profile if EAGAIN occurs.
Change-Id: I1a6c91fc348a20804b06d0bb64fbcd17cccea20f
Reviewed-on: https://chromium-review.googlesource.com/924246
Cr-Commit-Position: refs/heads/master@{#538474}

Bug: 801889
Change-Id: I421f83dfa58ad2990e4f6fe304f9713cfa9d6b60
Reviewed-on: https://chromium-review.googlesource.com/935664
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#579}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
3 files changed