Make UBSan warnings fatal and fix the existing ones

webrtc/modules/pacing/alr_detector.cc

 /*
  *  Copyright (c) 2016 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 49 matching lines @@
     alr_started_time_ms_.emplace(rtc::TimeMillis());
   } else if (alr_budget_.budget_level_percent() <
                  alr_stop_budget_level_percent_ &&
              alr_started_time_ms_) {
     alr_started_time_ms_.reset();
   }
 }
 
 void AlrDetector::SetEstimatedBitrate(int bitrate_bps) {
   RTC_DCHECK(bitrate_bps);
-  alr_budget_.set_target_rate_kbps(bitrate_bps * bandwidth_usage_percent_ /
-                                   (1000 * 100));
+  int64_t target_rate_kbps = int64_t{bitrate_bps} * bandwidth_usage_percent_ /

[kwiberg-webrtc, 2017/09/04 08:53:59]

Consider replacing the first "int64_t" with "auto". That way, you're guaranteed
to not get a narrowing conversion when you save the value to a temporary.

(Also consider making the temporary const. It's not all that necessary given
that it only lives one more line, but it's a good habit to get into.)

[oprypin_webrtc, 2017/09/04 09:09:21]

Done.

+                             (1000 * 100);
+  alr_budget_.set_target_rate_kbps(rtc::dchecked_cast<int>(target_rate_kbps));
 }
 
 rtc::Optional<int64_t> AlrDetector::GetApplicationLimitedRegionStartTime()
     const {
   return alr_started_time_ms_;
 }
 
 rtc::Optional<AlrDetector::AlrExperimentSettings>
 AlrDetector::ParseAlrSettingsFromFieldTrial(const char* experiment_name) {
   rtc::Optional<AlrExperimentSettings> ret;
@@ skipping 28 matching lines @@
                  << settings.alr_stop_budget_level_percent
                  << ", ALR experiment group ID: " << settings.group_id;
   } else {
     LOG(LS_INFO) << "Failed to parse ALR experiment: " << experiment_name;
   }
 
   return ret;
 }
 
 }  // namespace webrtc