Fix ubsan warnings in BWE tests.

webrtc/modules/remote_bitrate_estimator/test/estimators/nada.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  *
  */
@@ skipping 160 matching lines @@
 
 int NadaBweSender::GetFeedbackIntervalMs() const {
   return 100;
 }
 
 void NadaBweSender::GiveFeedback(const FeedbackPacket& feedback) {
   const NadaFeedback& fb = static_cast<const NadaFeedback&>(feedback);
 
   // Following parameters might be optimized.
   const int64_t kQueuingDelayUpperBoundMs = 10;
-  const float kDerivativeUpperBound = 10.0f / min_feedback_delay_ms_;
+  const float kDerivativeUpperBound =
+      10.0f / std::max<int64_t>(1, min_feedback_delay_ms_);
   // In the modified version, a higher kMinUpperBound allows a higher d_hat
   // upper bound for calling AcceleratedRampUp.
   const float kProportionalityDelayBits = 20.0f;
 
   int64_t now_ms = clock_->TimeInMilliseconds();
   float delta_s = now_ms - last_feedback_ms_;
   last_feedback_ms_ = now_ms;
   // Update delta_0.
   min_feedback_delay_ms_ =
       std::min(min_feedback_delay_ms_, static_cast<int64_t>(delta_s));
@@ skipping 87 matching lines @@
                         (kTheta - (bitrate_kbps_ - kMinBitrateKbps) * x_hat)) /
                            (kTauOMs * kTauOMs) +
                        0.5f);
 
   bitrate_kbps_ = bitrate_kbps_ + smoothing_factor * original_increase;
 }
 
 }  // namespace bwe
 }  // namespace testing
 }  // namespace webrtc