Remove use of stl_util's STLDeleteContainerPairSecondPointers from content/.

content/browser/renderer_host/p2p/socket_host_tcp_unittest.cc

Index: content/browser/renderer_host/p2p/socket_host_tcp_unittest.cc
diff --git a/content/browser/renderer_host/p2p/socket_host_tcp_unittest.cc b/content/browser/renderer_host/p2p/socket_host_tcp_unittest.cc
index 7174fb1ac50a42da92d1df01674a14c785224737..b018b2741ccfbf5c50227f3c0c2b92275b627b22 100644
--- a/content/browser/renderer_host/p2p/socket_host_tcp_unittest.cc
+++ b/content/browser/renderer_host/p2p/socket_host_tcp_unittest.cc
@@ -38,10 +38,10 @@ class P2PSocketHostTcpTestBase : public testing::Test {
 
     if (socket_type_ == P2P_SOCKET_TCP_CLIENT) {
       socket_host_.reset(
-          new P2PSocketHostTcp(&sender_, 0, P2P_SOCKET_TCP_CLIENT, NULL));
+          new P2PSocketHostTcp(&sender_, 0, P2P_SOCKET_TCP_CLIENT, nullptr));
     } else {
       socket_host_.reset(new P2PSocketHostStunTcp(
-          &sender_, 0, P2P_SOCKET_STUN_TCP_CLIENT, NULL));
+          &sender_, 0, P2P_SOCKET_STUN_TCP_CLIENT, nullptr));
     }
 
     socket_ = new FakeSocket(&sent_data_);