Replace ABSL_FALLTHROUGH_INTENDED with c++17 attribute

the new spelling is more standard and more compact, in particular doesn't need extra include and thus dependency

Bug: None
Change-Id: Iaea69d2154e4d9eff2468514f5734cb3fe016ff8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/245080
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35709}
diff --git a/api/video_codecs/video_decoder_software_fallback_wrapper.cc b/api/video_codecs/video_decoder_software_fallback_wrapper.cc
index 6b8211c..6484616 100644
--- a/api/video_codecs/video_decoder_software_fallback_wrapper.cc
+++ b/api/video_codecs/video_decoder_software_fallback_wrapper.cc
@@ -16,7 +16,6 @@
 #include <string>
 #include <utility>
 
-#include "absl/base/macros.h"
 #include "api/video/encoded_image.h"
 #include "api/video_codecs/video_decoder.h"
 #include "modules/video_coding/include/video_error_codes.h"
@@ -209,7 +208,7 @@
       }
 
       // Fallback decoder initialized, fall-through.
-      ABSL_FALLTHROUGH_INTENDED;
+      [[fallthrough]];
     }
     case DecoderType::kFallback:
       return fallback_decoder_->Decode(input_image, missing_frames,
diff --git a/api/video_codecs/video_encoder_software_fallback_wrapper.cc b/api/video_codecs/video_encoder_software_fallback_wrapper.cc
index 72e08a7..39c52a0 100644
--- a/api/video_codecs/video_encoder_software_fallback_wrapper.cc
+++ b/api/video_codecs/video_encoder_software_fallback_wrapper.cc
@@ -155,7 +155,7 @@
         RTC_LOG(LS_WARNING)
             << "Trying to access encoder in uninitialized fallback wrapper.";
         // Return main encoder to preserve previous behavior.
-        ABSL_FALLTHROUGH_INTENDED;
+        [[fallthrough]];
       case EncoderState::kMainEncoderUsed:
         return encoder_.get();
       case EncoderState::kFallbackDueToFailure:
diff --git a/call/adaptation/video_stream_adapter.cc b/call/adaptation/video_stream_adapter.cc
index c6560b3..3d4c4dd 100644
--- a/call/adaptation/video_stream_adapter.cc
+++ b/call/adaptation/video_stream_adapter.cc
@@ -375,7 +375,7 @@
         return increase_frame_rate;
       }
       // else, increase resolution.
-      ABSL_FALLTHROUGH_INTENDED;
+      [[fallthrough]];
     }
     case DegradationPreference::MAINTAIN_FRAMERATE: {
       // Attempt to increase pixel count.
@@ -459,7 +459,7 @@
         return decrease_frame_rate;
       }
       // else, decrease resolution.
-      ABSL_FALLTHROUGH_INTENDED;
+      [[fallthrough]];
     }
     case DegradationPreference::MAINTAIN_FRAMERATE: {
       return DecreaseResolution(input_state, current_restrictions);
diff --git a/modules/rtp_rtcp/source/video_rtp_depacketizer_h264.cc b/modules/rtp_rtcp/source/video_rtp_depacketizer_h264.cc
index e87be03..ee4d744 100644
--- a/modules/rtp_rtcp/source/video_rtp_depacketizer_h264.cc
+++ b/modules/rtp_rtcp/source/video_rtp_depacketizer_h264.cc
@@ -15,7 +15,6 @@
 #include <utility>
 #include <vector>
 
-#include "absl/base/macros.h"
 #include "absl/types/optional.h"
 #include "absl/types/variant.h"
 #include "common_video/h264/h264_common.h"
@@ -197,7 +196,7 @@
       case H264::NaluType::kIdr:
         parsed_payload->video_header.frame_type =
             VideoFrameType::kVideoFrameKey;
-        ABSL_FALLTHROUGH_INTENDED;
+        [[fallthrough]];
       case H264::NaluType::kSlice: {
         absl::optional<uint32_t> pps_id = PpsParser::ParsePpsIdFromSlice(
             &payload_data[start_offset], end_offset - start_offset);
diff --git a/modules/video_coding/rtp_seq_num_only_ref_finder.cc b/modules/video_coding/rtp_seq_num_only_ref_finder.cc
index 4381cf0..59b027e 100644
--- a/modules/video_coding/rtp_seq_num_only_ref_finder.cc
+++ b/modules/video_coding/rtp_seq_num_only_ref_finder.cc
@@ -116,7 +116,7 @@
         case kHandOff:
           complete_frame = true;
           res.push_back(std::move(*frame_it));
-          ABSL_FALLTHROUGH_INTENDED;
+          [[fallthrough]];
         case kDrop:
           frame_it = stashed_frames_.erase(frame_it);
       }
diff --git a/modules/video_coding/rtp_vp8_ref_finder.cc b/modules/video_coding/rtp_vp8_ref_finder.cc
index 66cddac..64f1bae 100644
--- a/modules/video_coding/rtp_vp8_ref_finder.cc
+++ b/modules/video_coding/rtp_vp8_ref_finder.cc
@@ -218,7 +218,7 @@
         case kHandOff:
           complete_frame = true;
           res.push_back(std::move(*frame_it));
-          ABSL_FALLTHROUGH_INTENDED;
+          [[fallthrough]];
         case kDrop:
           frame_it = stashed_frames_.erase(frame_it);
       }
diff --git a/modules/video_coding/rtp_vp9_ref_finder.cc b/modules/video_coding/rtp_vp9_ref_finder.cc
index cab5792..fd271f8 100644
--- a/modules/video_coding/rtp_vp9_ref_finder.cc
+++ b/modules/video_coding/rtp_vp9_ref_finder.cc
@@ -314,7 +314,7 @@
         case kHandOff:
           complete_frame = true;
           res.push_back(std::move(*frame_it));
-          ABSL_FALLTHROUGH_INTENDED;
+          [[fallthrough]];
         case kDrop:
           frame_it = stashed_frames_.erase(frame_it);
       }
diff --git a/net/dcsctp/socket/dcsctp_socket.cc b/net/dcsctp/socket/dcsctp_socket.cc
index 8153910..27a9ff4 100644
--- a/net/dcsctp/socket/dcsctp_socket.cc
+++ b/net/dcsctp/socket/dcsctp_socket.cc
@@ -494,17 +494,13 @@
     case State::kClosed:
       return SocketState::kClosed;
     case State::kCookieWait:
-      ABSL_FALLTHROUGH_INTENDED;
     case State::kCookieEchoed:
       return SocketState::kConnecting;
     case State::kEstablished:
       return SocketState::kConnected;
     case State::kShutdownPending:
-      ABSL_FALLTHROUGH_INTENDED;
     case State::kShutdownSent:
-      ABSL_FALLTHROUGH_INTENDED;
     case State::kShutdownReceived:
-      ABSL_FALLTHROUGH_INTENDED;
     case State::kShutdownAckSent:
       return SocketState::kShuttingDown;
   }
diff --git a/sdk/objc/native/src/audio/voice_processing_audio_unit.mm b/sdk/objc/native/src/audio/voice_processing_audio_unit.mm
index 661022f..3905b68 100644
--- a/sdk/objc/native/src/audio/voice_processing_audio_unit.mm
+++ b/sdk/objc/native/src/audio/voice_processing_audio_unit.mm
@@ -10,7 +10,6 @@
 
 #import "voice_processing_audio_unit.h"
 
-#include "absl/base/macros.h"
 #include "rtc_base/checks.h"
 #include "system_wrappers/include/metrics.h"
 
@@ -466,13 +465,11 @@
     switch (state_) {
       case kStarted:
         Stop();
-        // Fall through.
-        ABSL_FALLTHROUGH_INTENDED;
+        [[fallthrough]];
       case kInitialized:
         Uninitialize();
         break;
       case kUninitialized:
-        ABSL_FALLTHROUGH_INTENDED;
       case kInitRequired:
         break;
     }
diff --git a/video/rtp_video_stream_receiver.cc b/video/rtp_video_stream_receiver.cc
index 5a1b90b..7caa78b 100644
--- a/video/rtp_video_stream_receiver.cc
+++ b/video/rtp_video_stream_receiver.cc
@@ -17,7 +17,6 @@
 #include <vector>
 
 #include "absl/algorithm/container.h"
-#include "absl/base/macros.h"
 #include "absl/memory/memory.h"
 #include "absl/types/optional.h"
 #include "media/base/media_constants.h"
@@ -620,7 +619,7 @@
       case video_coding::H264SpsPpsTracker::kRequestKeyframe:
         rtcp_feedback_buffer_.RequestKeyFrame();
         rtcp_feedback_buffer_.SendBufferedRtcpFeedback();
-        ABSL_FALLTHROUGH_INTENDED;
+        [[fallthrough]];
       case video_coding::H264SpsPpsTracker::kDrop:
         return;
       case video_coding::H264SpsPpsTracker::kInsert:
diff --git a/video/rtp_video_stream_receiver2.cc b/video/rtp_video_stream_receiver2.cc
index 78ab9a4..3a3e895 100644
--- a/video/rtp_video_stream_receiver2.cc
+++ b/video/rtp_video_stream_receiver2.cc
@@ -17,7 +17,6 @@
 #include <vector>
 
 #include "absl/algorithm/container.h"
-#include "absl/base/macros.h"
 #include "absl/memory/memory.h"
 #include "absl/types/optional.h"
 #include "api/video/video_codec_type.h"
@@ -603,7 +602,7 @@
       case video_coding::H264SpsPpsTracker::kRequestKeyframe:
         rtcp_feedback_buffer_.RequestKeyFrame();
         rtcp_feedback_buffer_.SendBufferedRtcpFeedback();
-        ABSL_FALLTHROUGH_INTENDED;
+        [[fallthrough]];
       case video_coding::H264SpsPpsTracker::kDrop:
         return;
       case video_coding::H264SpsPpsTracker::kInsert: