Remove unused lambda capture to unbreak downstream code.

webrtc/p2p/base/p2ptransportchannel.cc

Index: webrtc/p2p/base/p2ptransportchannel.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index 532d35cc54027a3aeaab907ec6687086031d4410..7819ce8a44d0e16116749c66b8d1e5803a823283 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -1691,7 +1691,7 @@ Connection* P2PTransportChannel::FindNextPingableConnection() {
                [this, now](Connection* conn) { return IsPingable(conn, now); });
   auto iter =
       std::max_element(pingable_connections.begin(), pingable_connections.end(),
-                       [this, now](Connection* conn1, Connection* conn2) {
+                       [this](Connection* conn1, Connection* conn2) {
                          return MorePingable(conn1, conn2) == conn2;
                        });
   if (iter != pingable_connections.end()) {