Provision to start base::SimpleTestTickClock at initial ticks

media/cast/net/rtp/rtp_packetizer_unittest.cc

Index: media/cast/net/rtp/rtp_packetizer_unittest.cc
diff --git a/media/cast/net/rtp/rtp_packetizer_unittest.cc b/media/cast/net/rtp/rtp_packetizer_unittest.cc
index e15647e17635d58cd68b431e9885d32ca581947f..c5a50dae90df06ccd71453a7339635f6a0905242 100644
--- a/media/cast/net/rtp/rtp_packetizer_unittest.cc
+++ b/media/cast/net/rtp/rtp_packetizer_unittest.cc
@@ -108,7 +108,8 @@ class TestRtpPacketTransport : public PacketSender {
 class RtpPacketizerTest : public ::testing::Test {
  protected:
   RtpPacketizerTest()
-      : task_runner_(new test::FakeSingleThreadTaskRunner(&testing_clock_)) {
+      : testing_clock_(base::TimeTicks()),
+        task_runner_(new test::FakeSingleThreadTaskRunner(&testing_clock_)) {
     config_.sequence_number = kSeqNum;
     config_.ssrc = kSsrc;
     config_.payload_type = kPayload;