[AudioService] Fix audio sandbox policy knob.

http://crrev.com/c/1831763 introduced a policy to make sure that
enterprises can explicitly control the audio sandbox. The CL assumed
that all calls of IsAudioSandboxEnabled() would happen on the browser

It was, however, noticed that this is not the case as
IsAudioSandboxEnabled() is called on the audio utility process to
configure the sandbox. This caused the sandbox to always be enabled,
since the default value for g_audio_sandbox_enabled is true.

This CL fixes the behavior by replacing the global static variable with
a switch which is then copied over to the audio utility process.

(cherry picked from commit 3a7be23368f36d2a6e7092c27823309d7f1732c9)

Bug: 1018580
Change-Id: I810ca1f0c9aed43b892c06960cd8a87fc6debd8b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1901029
Reviewed-by: Will Harris <wfh@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Armando Miraglia <armax@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#713680}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1908530
Reviewed-by: Armando Miraglia <armax@chromium.org>
Cr-Commit-Position: refs/branch-heads/3945@{#560}
Cr-Branched-From: e4635fff7defbae0f9c29e798349f6fc0cce4b1b-refs/heads/master@{#706915}
5 files changed