`RtpSource`: remove deprecated ctor, use designated initializers

Bug: webrtc:10739, b/246753278
Change-Id: I215483709e1f415170bc42ea6d523ffad8eb1e76
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/275561
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38085}
diff --git a/api/transport/rtp/rtp_source.h b/api/transport/rtp/rtp_source.h
index 8c543ca..c19cfeb 100644
--- a/api/transport/rtp/rtp_source.h
+++ b/api/transport/rtp/rtp_source.h
@@ -33,19 +33,6 @@
 
   RtpSource() = delete;
 
-  // TODO(bugs.webrtc.org/10739): Remove this constructor once all clients
-  // migrate to the version with absolute capture time.
-  RtpSource(int64_t timestamp_ms,
-            uint32_t source_id,
-            RtpSourceType source_type,
-            absl::optional<uint8_t> audio_level,
-            uint32_t rtp_timestamp)
-      : RtpSource(timestamp_ms,
-                  source_id,
-                  source_type,
-                  rtp_timestamp,
-                  {audio_level, absl::nullopt}) {}
-
   RtpSource(int64_t timestamp_ms,
             uint32_t source_id,
             RtpSourceType source_type,
diff --git a/modules/rtp_rtcp/source/source_tracker_unittest.cc b/modules/rtp_rtcp/source/source_tracker_unittest.cc
index b64f03c..4cd8ab8 100644
--- a/modules/rtp_rtcp/source/source_tracker_unittest.cc
+++ b/modules/rtp_rtcp/source/source_tracker_unittest.cc
@@ -266,10 +266,12 @@
                      kAbsoluteCaptureTime, kReceiveTime1)}));
 
   int64_t timestamp_ms = clock.TimeInMilliseconds();
-  constexpr RtpSource::Extensions extensions0 = {kAudioLevel0,
-                                                 kAbsoluteCaptureTime};
-  constexpr RtpSource::Extensions extensions1 = {kAudioLevel1,
-                                                 kAbsoluteCaptureTime};
+  constexpr RtpSource::Extensions extensions0 = {
+      .audio_level = kAudioLevel0,
+      .absolute_capture_time = kAbsoluteCaptureTime};
+  constexpr RtpSource::Extensions extensions1 = {
+      .audio_level = kAudioLevel1,
+      .absolute_capture_time = kAbsoluteCaptureTime};
 
   EXPECT_THAT(tracker.GetSources(),
               ElementsAre(RtpSource(timestamp_ms, kSsrc2, RtpSourceType::SSRC,
@@ -354,12 +356,15 @@
   constexpr Timestamp kReceiveTime1 = Timestamp::Millis(61);
   constexpr Timestamp kReceiveTime2 = Timestamp::Millis(62);
 
-  constexpr RtpSource::Extensions extensions0 = {kAudioLevel0,
-                                                 kAbsoluteCaptureTime0};
-  constexpr RtpSource::Extensions extensions1 = {kAudioLevel1,
-                                                 kAbsoluteCaptureTime1};
-  constexpr RtpSource::Extensions extensions2 = {kAudioLevel2,
-                                                 kAbsoluteCaptureTime2};
+  constexpr RtpSource::Extensions extensions0 = {
+      .audio_level = kAudioLevel0,
+      .absolute_capture_time = kAbsoluteCaptureTime0};
+  constexpr RtpSource::Extensions extensions1 = {
+      .audio_level = kAudioLevel1,
+      .absolute_capture_time = kAbsoluteCaptureTime1};
+  constexpr RtpSource::Extensions extensions2 = {
+      .audio_level = kAudioLevel2,
+      .absolute_capture_time = kAbsoluteCaptureTime2};
 
   SimulatedClock clock(1000000000000ULL);
   SourceTracker tracker(&clock);
@@ -453,8 +458,9 @@
 
   clock.AdvanceTimeMilliseconds(SourceTracker::kTimeoutMs);
 
-  constexpr RtpSource::Extensions extensions1 = {kAudioLevel1,
-                                                 kAbsoluteCaptureTime1};
+  constexpr RtpSource::Extensions extensions1 = {
+      .audio_level = kAudioLevel1,
+      .absolute_capture_time = kAbsoluteCaptureTime1};
 
   EXPECT_THAT(
       tracker.GetSources(),