Switching AudioOutputAuthorizationHandler from using AudioManager interface to AudioSystem one.

BUG=672468
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2692203003
Cr-Commit-Position: refs/heads/master@{#450939}
  void GetInterface(const std::string& interface_name,
                    mojo::ScopedMessagePipeHandle handle) {
    DCHECK(thread_checker_.CalledOnValidThread());
    DCHECK_CURRENTLY_ON(BrowserThread::IO);
    service_manager::mojom::InterfaceProvider* provider = registry_.get();

    base::AutoLock lock(enabled_lock_);
    if (enabled_)
      provider->GetInterface(interface_name, std::move(handle));
  }

  void GetInterface(const std::string& interface_name,
                    mojo::ScopedMessagePipeHandle handle) {
    DCHECK(thread_checker_.CalledOnValidThread());
    DCHECK_CURRENTLY_ON(BrowserThread::IO);
    service_manager::mojom::InterfaceProvider* provider = registry_.get();

    base::AutoLock lock(enabled_lock_);
    if (enabled_)
      provider->GetInterface(interface_name, std::move(handle));
  }
