[fuchsia] Enable UDPSocketTest.JoinMulticastGroup

Assert after each send call to better pinpoint future problems.

The test passes locally.

Fixed: 1125855
Change-Id: I30d5c7bd2bc14fbd9547b1eb6d309d7556274891
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2404483
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Tamir Duberstein <tamird@google.com>
Cr-Commit-Position: refs/heads/master@{#806111}

services/network/udp_socket_unittest.cc

@@ -691,8 +691,7 @@ TEST_F(UDPSocketTest, MAYBE_JoinMulticastGroup) {
   mojom::UDPSocketOptionsPtr options = mojom::UDPSocketOptions::New();
   options->allow_address_sharing_for_multicast = true;
 
-  net::IPAddress bind_ip_address;
-  EXPECT_TRUE(bind_ip_address.AssignFromIPLiteral("0.0.0.0"));
+  net::IPAddress bind_ip_address = net::IPAddress::AllZeros(group_ip.size());
   net::IPEndPoint socket_address(bind_ip_address, 0);
   ASSERT_EQ(net::OK, helper.BindSync(socket_address, std::move(options),
                                      &socket_address));
@@ -741,10 +740,14 @@ TEST_F(UDPSocketTest, MAYBE_JoinMulticastGroup) {
 
   // No longer can receive messages from itself or from second socket.
   EXPECT_EQ(net::OK, helper.SendToSync(group_alias, test_msg));
-  ASSERT_EQ(net::OK, second_socket_helper.SendToSync(group_alias, test_msg));
   socket_remote->ReceiveMore(1);
   socket_remote.FlushForTesting();
-  ASSERT_EQ(2u, listener.results().size());
+  EXPECT_EQ(2u, listener.results().size());
+
+  EXPECT_EQ(net::OK, second_socket_helper.SendToSync(group_alias, test_msg));
+  socket_remote->ReceiveMore(1);
+  socket_remote.FlushForTesting();
+  EXPECT_EQ(2u, listener.results().size());
 }
 
 TEST_F(UDPSocketTest, ErrorHappensDuringSocketOptionsConfiguration) {

testing/buildbot/filters/fuchsia.services_unittests.filter

@@ -1,5 +1,2 @@
 # https://crbug.com/1125854 - IsTracingEnabled() expectations not met.
 -TracingConsumerTest.NotifiesOnTracingEnabledWaitsFor*
-
-# https://crbug.com/1125855 - Second socket receives too many packets.
--UDPSocketTest.JoinMulticastGroup