Delete struct rtc::PacketTime.

Replaced by a int64_t representing time in us. To aid transition of
downstream code, rtc::PacketTime is made an alias for int64_t.

Bug: webrtc:9584
Change-Id: Ic3a5ee87d6de2aad7712894906dab074f1443df9
Reviewed-on: https://webrtc-review.googlesource.com/c/91860
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25503}
diff --git a/pc/rtptransport.h b/pc/rtptransport.h
index 793ac90..dab5903 100644
--- a/pc/rtptransport.h
+++ b/pc/rtptransport.h
@@ -87,7 +87,7 @@
   RtpTransportAdapter* GetInternal() override;
 
   // These methods will be used in the subclasses.
-  void DemuxPacket(rtc::CopyOnWriteBuffer* packet, const rtc::PacketTime& time);
+  void DemuxPacket(rtc::CopyOnWriteBuffer* packet, int64_t packet_time_us);
 
   bool SendPacket(bool rtcp,
                   rtc::CopyOnWriteBuffer* packet,
@@ -98,9 +98,9 @@
   virtual void OnNetworkRouteChanged(
       absl::optional<rtc::NetworkRoute> network_route);
   virtual void OnRtpPacketReceived(rtc::CopyOnWriteBuffer* packet,
-                                   const rtc::PacketTime& packet_time);
+                                   int64_t packet_time_us);
   virtual void OnRtcpPacketReceived(rtc::CopyOnWriteBuffer* packet,
-                                    const rtc::PacketTime& packet_time);
+                                    int64_t packet_time_us);
   // Overridden by SrtpTransport and DtlsSrtpTransport.
   virtual void OnWritableState(rtc::PacketTransportInternal* packet_transport);
 
@@ -111,7 +111,7 @@
   void OnReadPacket(rtc::PacketTransportInternal* transport,
                     const char* data,
                     size_t len,
-                    const rtc::PacketTime& packet_time,
+                    const int64_t& packet_time_us,
                     int flags);
 
   // Updates "ready to send" for an individual channel and fires