[TaskScheduler]: Migrate off of AssertBlockingAllowedDeprecated in /media/audio

base::AssertBlockingAllowedDeprecated is deprecated in favor of
ScopedBlockingCall, which serves as a precise annotation of
the scope that may/will block.

Please make sure of the following:
  - ScopedBlockingCall is instantiated in a scope with minimal CPU usage.
    If this is not the case, ScopedBlockingCall should be instantiated
    closer to the blocking call. See scoped_blocking_call.h for more
    info. Please let me know when/where the blocking call happens if this needs
    to be changed.
  - Parameter |blocking_type| matches expectation:
      MAY_BLOCK: The call might block (e.g. file I/O that might hit in memory cache).
      WILL_BLOCK: The call will definitely block (e.g. cache already checked and now pinging
        server synchronously).
    See BlockingType for more info. While I assumed MAY_BLOCK by default, that might
    not be the best fit if we know that this callsite is guaranteed to block.
  - The ScopedBlockingCall's scope covers the entirety of the blocking operation
    previously asserted against by the AssertBlockingAllowed().
  - Calls to blocking //base APIs don't need to be annotated
    with ScopedBlockingCall. All blocking //base APIs (e.g. base::ReadFileToString, base::File::Read,
    base::SysInfo::AmountOfFreeDiskSpace, base::WaitableEvent::Wait, etc.) have their
    own internal annotations.

Refer to the top-level CL if necessary :
https://chromium-review.googlesource.com/c/chromium/src/+/1338391

Please CQ if LGTY!

This CL was uploaded by git cl split.

R=henrika@chromium.org

Bug: 903957
Change-Id: Id9a9bb29d5d9beb2f680472602badc3a1ac1f6e3
Reviewed-on: https://chromium-review.googlesource.com/c/1338126Reviewed-by: Max Morin <maxmorin@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608866}

media/audio/audio_debug_file_writer.cc

@@ -13,7 +13,6 @@
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/sys_byteorder.h"
-#include "base/threading/thread_restrictions.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_sample_types.h"
 
@@ -252,7 +251,6 @@ void AudioDebugFileWriter::AudioFileWriter::WriteHeader() {
 void AudioDebugFileWriter::AudioFileWriter::StartRecording(base::File file) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!file_.IsValid());
-  base::AssertBlockingAllowedDeprecated();
 
   file_ = std::move(file);
   WriteHeader();