To mitigate the effects of hanging 0-RTT QUIC connections,

net/quic/quic_network_transaction_unittest.cc

Index: net/quic/quic_network_transaction_unittest.cc
diff --git a/net/quic/quic_network_transaction_unittest.cc b/net/quic/quic_network_transaction_unittest.cc
index 14037efc236b88c5dc2fef4f420cd19ee1ff5295..af6fb7b2f9e27697eb107f425bbc345f580ac8c8 100644
--- a/net/quic/quic_network_transaction_unittest.cc
+++ b/net/quic/quic_network_transaction_unittest.cc
@@ -860,6 +860,34 @@ TEST_P(QuicNetworkTransactionTest, FailedZeroRttBrokenAlternateProtocol) {
   EXPECT_TRUE(quic_data.at_write_eof());
 }
 
+TEST_P(QuicNetworkTransactionTest, HangingZeroRttFallback) {
+  // Alternate-protocol job
+  MockRead quic_reads[] = {
+    MockRead(ASYNC, ERR_IO_PENDING),
+  };
+  StaticSocketDataProvider quic_data(quic_reads, arraysize(quic_reads),
+                                     NULL, 0);
+  socket_factory_.AddSocketDataProvider(&quic_data);
+
+  // Main job that will proceed when the QUIC job fails.
+  MockRead http_reads[] = {
+    MockRead("HTTP/1.1 200 OK\r\n\r\n"),
+    MockRead("hello from http"),
+    MockRead(SYNCHRONOUS, ERR_TEST_PEER_CLOSE_AFTER_NEXT_MOCK_READ),
+    MockRead(ASYNC, OK)
+  };
+
+  StaticSocketDataProvider http_data(http_reads, arraysize(http_reads),
+                                     NULL, 0);
+  socket_factory_.AddSocketDataProvider(&http_data);
+
+  CreateSessionWithNextProtos();
+
+  AddQuicAlternateProtocolMapping(MockCryptoClientStream::ZERO_RTT);
+
+  SendRequestAndExpectHttpResponse("hello from http");
+}
+
 TEST_P(QuicNetworkTransactionTest, BrokenAlternateProtocolOnConnectFailure) {
   // Alternate-protocol job will fail before creating a QUIC session.
   StaticSocketDataProvider quic_data(NULL, 0, NULL, 0);