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/media/base/fakemediaengine.h b/media/base/fakemediaengine.h
index acd3faa..32f6123 100644
--- a/media/base/fakemediaengine.h
+++ b/media/base/fakemediaengine.h
@@ -269,11 +269,11 @@
     recv_rtcp_parameters_ = params;
   }
   virtual void OnPacketReceived(rtc::CopyOnWriteBuffer* packet,
-                                const rtc::PacketTime& packet_time) {
+                                int64_t packet_time_us) {
     rtp_packets_.push_back(std::string(packet->data<char>(), packet->size()));
   }
   virtual void OnRtcpReceived(rtc::CopyOnWriteBuffer* packet,
-                              const rtc::PacketTime& packet_time) {
+                              int64_t packet_time_us) {
     rtcp_packets_.push_back(std::string(packet->data<char>(), packet->size()));
   }
   virtual void OnReadyToSend(bool ready) { ready_to_send_ = ready; }