compare Optional<unsigned> only to unsigned integers

more standard optional<T> inlines compares instead of converting second argument to T.
that leads to warnings about comparing unsigned to signed integers.

Bug: webrtc:9078
Change-Id: I43cc729d3b85d789b0c394064dc7e11dc27a37aa
Reviewed-on: https://webrtc-review.googlesource.com/66782
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22779}
diff --git a/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl_unittest.cc b/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl_unittest.cc
index c437918..574b699 100644
--- a/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl_unittest.cc
+++ b/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl_unittest.cc
@@ -314,12 +314,12 @@
 
   auto ana_stats = states.audio_network_adaptor->GetStats();
 
-  EXPECT_EQ(ana_stats.bitrate_action_counter, 2);
-  EXPECT_EQ(ana_stats.channel_action_counter, 2);
-  EXPECT_EQ(ana_stats.dtx_action_counter, 2);
-  EXPECT_EQ(ana_stats.fec_action_counter, 2);
-  EXPECT_EQ(ana_stats.frame_length_increase_counter, 1);
-  EXPECT_EQ(ana_stats.frame_length_decrease_counter, 1);
+  EXPECT_EQ(ana_stats.bitrate_action_counter, 2u);
+  EXPECT_EQ(ana_stats.channel_action_counter, 2u);
+  EXPECT_EQ(ana_stats.dtx_action_counter, 2u);
+  EXPECT_EQ(ana_stats.fec_action_counter, 2u);
+  EXPECT_EQ(ana_stats.frame_length_increase_counter, 1u);
+  EXPECT_EQ(ana_stats.frame_length_decrease_counter, 1u);
   EXPECT_EQ(ana_stats.uplink_packet_loss_fraction, 0.1f);
 }