Replace rtc::Optional with absl::optional in modules/audio_coding

This is a no-op change because rtc::Optional is an alias to absl::optional

This CL generated by running script with parameter 'modules/audio_coding'

find $@ -type f \( -name \*.h -o -name \*.cc \) \
-exec sed -i 's|rtc::Optional|absl::optional|g' {} \+ \
-exec sed -i 's|rtc::nullopt|absl::nullopt|g' {} \+ \
-exec sed -i 's|#include "api/optional.h"|#include "absl/types/optional.h"|' {} \+

find $@ -type f -name BUILD.gn \
-exec sed -r -i 's|"[\./api]*:optional"|"//third_party/abseil-cpp/absl/types:optional"|' {} \+;

git cl format

Bug: webrtc:9078
Change-Id: Ic980ee605148fdb160666d4aa03cc87175e48fe8
Reviewed-on: https://webrtc-review.googlesource.com/84130
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23659}
diff --git a/modules/audio_coding/acm2/acm_receiver.h b/modules/audio_coding/acm2/acm_receiver.h
index ce1e1f2..c0afbb1 100644
--- a/modules/audio_coding/acm2/acm_receiver.h
+++ b/modules/audio_coding/acm2/acm_receiver.h
@@ -16,9 +16,9 @@
 #include <string>
 #include <vector>
 
-#include "api/audio/audio_frame.h"
+#include "absl/types/optional.h"
 #include "api/array_view.h"
-#include "api/optional.h"
+#include "api/audio/audio_frame.h"
 #include "common_audio/vad/include/webrtc_vad.h"
 #include "modules/audio_coding/acm2/acm_resampler.h"
 #include "modules/audio_coding/acm2/call_statistics.h"
@@ -159,7 +159,7 @@
   // packet. If no packet of a registered non-CNG codec has been received, the
   // return value is empty. Also, if the decoder was unregistered since the last
   // packet was inserted, the return value is empty.
-  rtc::Optional<int> last_packet_sample_rate_hz() const;
+  absl::optional<int> last_packet_sample_rate_hz() const;
 
   // Returns last_output_sample_rate_hz from the NetEq instance.
   int last_output_sample_rate_hz() const;
@@ -195,7 +195,7 @@
 
   // Returns the RTP timestamp for the last sample delivered by GetAudio().
   // The return value will be empty if no valid timestamp is available.
-  rtc::Optional<uint32_t> GetPlayoutTimestamp();
+  absl::optional<uint32_t> GetPlayoutTimestamp();
 
   // Returns the current total delay from NetEq (packet buffer and sync buffer)
   // in ms, with smoothing applied to even out short-time fluctuations due to
@@ -215,7 +215,7 @@
   //
   int LastAudioCodec(CodecInst* codec) const;
 
-  rtc::Optional<SdpAudioFormat> LastAudioFormat() const;
+  absl::optional<SdpAudioFormat> LastAudioFormat() const;
 
   //
   // Get a decoder given its registered payload-type.
@@ -273,22 +273,23 @@
     int sample_rate_hz;
   };
 
-  const rtc::Optional<CodecInst> RtpHeaderToDecoder(const RTPHeader& rtp_header,
-                                                    uint8_t first_payload_byte)
-      const RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  const absl::optional<CodecInst> RtpHeaderToDecoder(
+      const RTPHeader& rtp_header,
+      uint8_t first_payload_byte) const
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
 
   uint32_t NowInTimestamp(int decoder_sampling_rate) const;
 
   rtc::CriticalSection crit_sect_;
-  rtc::Optional<CodecInst> last_audio_decoder_ RTC_GUARDED_BY(crit_sect_);
-  rtc::Optional<SdpAudioFormat> last_audio_format_ RTC_GUARDED_BY(crit_sect_);
+  absl::optional<CodecInst> last_audio_decoder_ RTC_GUARDED_BY(crit_sect_);
+  absl::optional<SdpAudioFormat> last_audio_format_ RTC_GUARDED_BY(crit_sect_);
   ACMResampler resampler_ RTC_GUARDED_BY(crit_sect_);
   std::unique_ptr<int16_t[]> last_audio_buffer_ RTC_GUARDED_BY(crit_sect_);
   CallStatistics call_stats_ RTC_GUARDED_BY(crit_sect_);
   const std::unique_ptr<NetEq> neteq_;  // NetEq is thread-safe; no lock needed.
   const Clock* const clock_;
   bool resampled_last_output_frame_ RTC_GUARDED_BY(crit_sect_);
-  rtc::Optional<int> last_packet_sample_rate_hz_ RTC_GUARDED_BY(crit_sect_);
+  absl::optional<int> last_packet_sample_rate_hz_ RTC_GUARDED_BY(crit_sect_);
 };
 
 }  // namespace acm2