Convert //media/cast from scoped_ptr to std::unique_ptr

media/cast/net/rtcp/test_rtcp_packet_builder.cc

Index: media/cast/net/rtcp/test_rtcp_packet_builder.cc
diff --git a/media/cast/net/rtcp/test_rtcp_packet_builder.cc b/media/cast/net/rtcp/test_rtcp_packet_builder.cc
index 48c9d59a12c4e7e924294c63ae8a6500911c311d..597ad410c501e82f2070926a3a9e98d13a2de619 100644
--- a/media/cast/net/rtcp/test_rtcp_packet_builder.cc
+++ b/media/cast/net/rtcp/test_rtcp_packet_builder.cc
@@ -229,9 +229,9 @@ void TestRtcpPacketBuilder::AddReceiverEventLog(uint16_t event_data,
   big_endian_writer_.WriteU16(type_and_delta);
 }
 
-scoped_ptr<media::cast::Packet> TestRtcpPacketBuilder::GetPacket() {
+std::unique_ptr<media::cast::Packet> TestRtcpPacketBuilder::GetPacket() {
   PatchLengthField();
-  return scoped_ptr<media::cast::Packet>(
+  return std::unique_ptr<media::cast::Packet>(
       new media::cast::Packet(buffer_, buffer_ + Length()));
 }