HttpStreamPool: Don't start QuicTask when failing

AttemptManager::MaybeAttemptQuic() should not start QuicTask when
`is_failing_` is true. Otherwise, we end up hitting CHECK(!is_failing_)
in AttemptManager::OnQuicTaskComplete() when a QUIC attempt completes
successfully.

Bug: 403341337
Change-Id: I06b50d92e16eff6c37061ad3af77331c8734b001
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6355632
Reviewed-by: Adam Rice <ricea@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1433916}

net/http/http_stream_pool_attempt_manager.cc

@@ -1277,7 +1277,7 @@ void HttpStreamPool::AttemptManager::MaybeNotifySSLConfigReady() {
 
 void HttpStreamPool::AttemptManager::MaybeAttemptQuic() {
   CHECK(service_endpoint_request_);
-  if (!CanUseQuic() || quic_task_result_.has_value() ||
+  if (is_failing_ || !CanUseQuic() || quic_task_result_.has_value() ||
       !service_endpoint_request_->EndpointsCryptoReady()) {
     return;
   }

net/http/http_stream_pool_attempt_manager_unittest.cc

@@ -4778,6 +4778,45 @@ TEST_F(HttpStreamPoolAttemptManagerTest, QuicOkDnsAlpn) {
               Optional(IsOk()));
 }
 
+// Regression test for crbug.com/403341337. QuicTask should not be started when
+// the corresponding AttemptManager is failing.
+TEST_F(HttpStreamPoolAttemptManagerTest, DontStartQuicAfterFailure) {
+  AddQuicData();
+
+  FakeServiceEndpointRequest* endpoint_request = resolver()->AddFakeRequest();
+
+  // Request a stream to create an AttemptManager.
+  StreamRequester requester;
+  requester.set_destination(kDefaultDestination)
+      .set_quic_version(quic_version())
+      .RequestStream(pool());
+  ASSERT_FALSE(requester.result().has_value());
+
+  // Simulate a network change event to fail the AttemptManager.
+  NetworkChangeNotifier::NotifyObserversOfIPAddressChangeForTests();
+  FastForwardUntilNoTasksRemain();
+
+  // Complete the service endpoint resolution. QuicTask should not start.
+  endpoint_request
+      ->add_endpoint(ServiceEndpointBuilder().add_v4("192.0.2.1").endpoint())
+      .CallOnServiceEndpointRequestFinished(OK);
+  requester.WaitForResult();
+  EXPECT_THAT(requester.result(), Optional(IsError(ERR_NETWORK_CHANGED)));
+  ASSERT_TRUE(pool()
+                  .GetGroupForTesting(requester.GetStreamKey())
+                  ->GetAttemptManagerForTesting()
+                  ->is_failing());
+  ASSERT_FALSE(pool()
+                   .GetGroupForTesting(requester.GetStreamKey())
+                   ->GetAttemptManagerForTesting()
+                   ->GetQuicTaskResultForTesting());
+
+  // Ensure that the attempt manager completes after the request is destroyed.
+  requester.ResetRequest();
+  WaitForAttemptManagerComplete(
+      *pool().GetGroupForTesting(requester.GetStreamKey()));
+}
+
 // Tests that QUIC is not attempted when marked broken.
 TEST_F(HttpStreamPoolAttemptManagerTest, QuicBroken) {
   AlternativeService alternative_service(NextProto::kProtoQUIC,