Prevent busy-looping PacedSender on small packets.

webrtc/modules/pacing/bitrate_prober_unittest.cc

Index: webrtc/modules/pacing/bitrate_prober_unittest.cc
diff --git a/webrtc/modules/pacing/bitrate_prober_unittest.cc b/webrtc/modules/pacing/bitrate_prober_unittest.cc
index c966f5cfa8deefb9abed4f977d4c91d0a400d47b..074964a0622d9f44ed284a2b9d3cbaea158d4b4d 100644
--- a/webrtc/modules/pacing/bitrate_prober_unittest.cc
+++ b/webrtc/modules/pacing/bitrate_prober_unittest.cc
@@ -27,6 +27,7 @@ TEST(BitrateProberTest, VerifyStatesAndTimeBetweenProbes) {
   prober.MaybeInitializeProbe(300000);
   EXPECT_TRUE(prober.IsProbing());
 
+  // First packet should probe as soon as possible.
   EXPECT_EQ(0, prober.TimeUntilNextProbe(now_ms));
   prober.PacketSent(now_ms, 1000);
 
@@ -48,4 +49,28 @@ TEST(BitrateProberTest, VerifyStatesAndTimeBetweenProbes) {
   EXPECT_EQ(-1, prober.TimeUntilNextProbe(now_ms));
   EXPECT_FALSE(prober.IsProbing());
 }
+
+TEST(BitrateProberTest, DoesntProbeWithoutRecentPackets) {
+  BitrateProber prober;
+  EXPECT_FALSE(prober.IsProbing());
+  int64_t now_ms = 0;
+  EXPECT_EQ(-1, prober.TimeUntilNextProbe(now_ms));
+
+  prober.SetEnabled(true);
+  EXPECT_FALSE(prober.IsProbing());
+
+  prober.MaybeInitializeProbe(300000);
+  EXPECT_TRUE(prober.IsProbing());
+  EXPECT_EQ(0, prober.TimeUntilNextProbe(now_ms));
+  // Let time pass, no large enough packets put into prober.
+  now_ms += 6000;
+  EXPECT_EQ(-1, prober.TimeUntilNextProbe(now_ms));
+  // Insert a small packet, not a candidate for probing.
+  prober.PacketSent(now_ms, 100);
+  EXPECT_EQ(-1, prober.TimeUntilNextProbe(now_ms));
+  // Insert a large-enough packet.
+  prober.PacketSent(now_ms, 1000);
+  EXPECT_EQ(8, prober.TimeUntilNextProbe(now_ms));
+}
+
 }  // namespace webrtc