Revert of Delete class SSRCDatabase, and its global ssrc registry.

webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
index 22fe71e5935bef5fdf29f5945b122760fc9aa96a..5c0ff1f1aeae44895003c2ee5657717b73f3906b 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
@@ -343,7 +343,6 @@
       false, &fake_clock_, &transport_, nullptr, nullptr, &seq_num_allocator_,
       &feedback_observer_, nullptr, nullptr, nullptr, &mock_rtc_event_log_,
       &send_packet_observer_, &retransmission_rate_limiter_, nullptr));
-  rtp_sender_->SetSSRC(kSsrc);
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionTransportSequenceNumber,
                    kTransportSequenceNumberExtensionId));
@@ -961,7 +960,7 @@
       new RTPSender(false, &fake_clock_, &transport_, &mock_paced_sender_,
                     nullptr, nullptr, nullptr, nullptr, &callback, nullptr,
                     nullptr, nullptr, &retransmission_rate_limiter_, nullptr));
-  rtp_sender_->SetSSRC(kSsrc);
+
   char payload_name[RTP_PAYLOAD_NAME_SIZE] = "GENERIC";
   const uint8_t payload_type = 127;
   ASSERT_EQ(0, rtp_sender_->RegisterPayload(payload_name, payload_type, 90000,
@@ -1023,7 +1022,6 @@
                                   nullptr, nullptr, nullptr, &callback, nullptr,
                                   nullptr, nullptr, nullptr,
                                   &retransmission_rate_limiter_, nullptr));
-  rtp_sender_->SetSSRC(kSsrc);
 
   // Simulate kNumPackets sent with kPacketInterval ms intervals, with the
   // number of packets selected so that we fill (but don't overflow) the one
@@ -1082,7 +1080,6 @@
                                     nullptr, nullptr, nullptr, nullptr, nullptr,
                                     nullptr, nullptr, nullptr,
                                     &retransmission_rate_limiter_, nullptr));
-    rtp_sender_->SetSSRC(kSsrc);
     rtp_sender_->SetSequenceNumber(kSeqNum);
   }
 };
@@ -1443,7 +1440,6 @@
       new RTPSender(false, &fake_clock_, &transport_, nullptr, nullptr, nullptr,
                     nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                     &retransmission_rate_limiter_, &mock_overhead_observer));
-  rtp_sender_->SetSSRC(kSsrc);
 
   // RTP overhead is 12B.
   EXPECT_CALL(mock_overhead_observer, OnOverheadChanged(12)).Times(1);
@@ -1464,7 +1460,6 @@
       new RTPSender(false, &fake_clock_, &transport_, nullptr, nullptr, nullptr,
                     nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                     &retransmission_rate_limiter_, &mock_overhead_observer));
-  rtp_sender_->SetSSRC(kSsrc);
 
   EXPECT_CALL(mock_overhead_observer, OnOverheadChanged(_)).Times(1);
   SendGenericPayload();
@@ -1480,7 +1475,6 @@
       false, &fake_clock_, &transport_, nullptr, nullptr, &seq_num_allocator_,
       &feedback_observer_, nullptr, nullptr, nullptr, &mock_rtc_event_log_,
       nullptr, &retransmission_rate_limiter_, &mock_overhead_observer));
-  rtp_sender_->SetSSRC(kSsrc);
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionTransportSequenceNumber,
                    kTransportSequenceNumberExtensionId));