Fix integer overflow in ProbeController.

webrtc/modules/congestion_controller/probe_controller_unittest.cc

Index: webrtc/modules/congestion_controller/probe_controller_unittest.cc
diff --git a/webrtc/modules/congestion_controller/probe_controller_unittest.cc b/webrtc/modules/congestion_controller/probe_controller_unittest.cc
index 61ca559a5364ae928ff5d8d023700f0d052e4671..6d025282bcadd2b62dc62fa4bfc3919123f9bcaa 100644
--- a/webrtc/modules/congestion_controller/probe_controller_unittest.cc
+++ b/webrtc/modules/congestion_controller/probe_controller_unittest.cc
@@ -83,8 +83,8 @@ TEST_F(ProbeControllerTest, TestExponentialProbing) {
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
 
-  // Repeated probe should only be sent when estimated bitrate climbs above 4 *
-  // kStartBitrateBps = 1200.
+  // Repeated probe should only be sent when estimated bitrate climbs above
+  // 0.7 * 6 * kStartBitrateBps = 1260.
   EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(0);
   probe_controller_->SetEstimatedBitrate(1000);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
@@ -160,5 +160,19 @@ TEST_F(ProbeControllerTest, PeriodicProbing) {
   testing::Mock::VerifyAndClearExpectations(&pacer_);
 }
 
+TEST_F(ProbeControllerTest, TestExponentialProbingOverflow) {
+  int kMbps = 1000000;

[philipel, 2016/12/14 09:33:44]

const int/int64_t kBitsPerSecond = 1000000;

kMbps = 1000000 sound like you set the rate to one million Mbps or 1000 Gbps.

[Sergey Ulanov, 2016/12/14 22:41:26]

Renamed to kMbpsMultiplier.

+  probe_controller_->SetBitrates(kMinBitrateBps, 10 * kMbps, 100 * kMbps);
+
+  // Verify that probe bitrate is capped at the specified max bitrate
+  EXPECT_CALL(pacer_, CreateProbeCluster(100 * kMbps, _));
+  probe_controller_->SetEstimatedBitrate(60 * kMbps);
+  testing::Mock::VerifyAndClearExpectations(&pacer_);
+
+  // Verify that repeated probes aren't sent.
+  EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(0);
+  probe_controller_->SetEstimatedBitrate(100 * kMbps);
+}
+
 }  // namespace test
 }  // namespace webrtc