Reland of Do not delete a connection in the turn port with permission error or refresh error.

webrtc/p2p/base/p2ptransportchannel_unittest.cc

Index: webrtc/p2p/base/p2ptransportchannel_unittest.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel_unittest.cc b/webrtc/p2p/base/p2ptransportchannel_unittest.cc
index e5e63a3fa0c23d212a17eccb3c8dd7915c4fa49f..87be379ffbe22ba20addfdd18f13a5cde682456b 100644
--- a/webrtc/p2p/base/p2ptransportchannel_unittest.cc
+++ b/webrtc/p2p/base/p2ptransportchannel_unittest.cc
@@ -2278,6 +2278,24 @@
   EXPECT_EQ(conn2, FindNextPingableConnectionAndPingIt(&ch));
 }
 
+TEST_F(P2PTransportChannelPingTest, TestFailedConnectionNotPingable) {
+  cricket::FakePortAllocator pa(rtc::Thread::Current(), nullptr);
+  cricket::P2PTransportChannel ch("Do not ping failed connections", 1, &pa);
+  PrepareChannel(&ch);
+  ch.Connect();
+  ch.MaybeStartGathering();
+  ch.AddRemoteCandidate(CreateHostCandidate("1.1.1.1", 1, 1));
+
+  cricket::Connection* conn1 = WaitForConnectionTo(&ch, "1.1.1.1", 1);
+  ASSERT_TRUE(conn1 != nullptr);
+
+  EXPECT_EQ(conn1, ch.FindNextPingableConnection());
+  conn1->Prune();  // A pruned connection may still be pingable.
+  EXPECT_EQ(conn1, ch.FindNextPingableConnection());
+  conn1->FailAndPrune();
+  EXPECT_TRUE(nullptr == ch.FindNextPingableConnection());
+}
+
 TEST_F(P2PTransportChannelPingTest, TestSignalStateChanged) {
   cricket::FakePortAllocator pa(rtc::Thread::Current(), nullptr);
   cricket::P2PTransportChannel ch("state change", 1, &pa);