Reland "Clean up old uses of AssistantAudioDecoderFactory"

This is a reland of 184873e8

The original CL had an extra ')' in audio_output_provider_impl.cc.
This CL fixes it.

Original change's description:
> Clean up old uses of AssistantAudioDecoderFactory
>
> This CL replaces the last use of old Mojo type of
> AssistantAudioDecoderFactory interface with
> mojo::Remote.
>
> Bug: 955171
> Change-Id: I16778198e4dc1b7a7693dbbc0f7b85ae4a3d6bbc
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1890454
> Reviewed-by: Ken Rockot <rockot@google.com>
> Reviewed-by: Tao Wu <wutao@chromium.org>
> Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
> Cr-Commit-Position: refs/heads/master@{#711712}

Bug: 955171
Change-Id: I559da6829ba6fb8914f08ee761b9f998ec3de98d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895265
Commit-Queue: Ken Rockot <rockot@google.com>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715311}

chromeos/services/assistant/platform/audio_output_provider_impl.cc

@@ -157,8 +157,8 @@ AudioOutputProviderImpl::AudioOutputProviderImpl(
       device_id_(device_id),
       media_session_(media_session) {
   client_->RequestAudioDecoderFactory(
-      mojo::MakeRequest(&audio_decoder_factory_ptr_));
-  audio_decoder_factory_ = audio_decoder_factory_ptr_.get();
+      audio_decoder_factory_remote_.BindNewPipeAndPassReceiver());
+  audio_decoder_factory_ = audio_decoder_factory_remote_.get();
 }
 
 AudioOutputProviderImpl::~AudioOutputProviderImpl() = default;

chromeos/services/assistant/platform/audio_output_provider_impl.h

@@ -21,6 +21,7 @@
 #include "libassistant/shared/public/platform_audio_output.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
+#include "mojo/public/cpp/bindings/remote.h"
 #include "services/audio/public/mojom/stream_factory.mojom.h"
 
 namespace chromeos {
@@ -68,7 +69,8 @@ class AudioOutputProviderImpl : public assistant_client::AudioOutputProvider {
   VolumeControlImpl volume_control_impl_;
   scoped_refptr<base::SequencedTaskRunner> main_task_runner_;
   scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
-  mojom::AssistantAudioDecoderFactoryPtr audio_decoder_factory_ptr_;
+  mojo::Remote<mojom::AssistantAudioDecoderFactory>
+      audio_decoder_factory_remote_;
   mojom::AssistantAudioDecoderFactory* audio_decoder_factory_;
   std::string device_id_;
   AssistantMediaSession* media_session_;