Revert of Pass time constant to bwe smoothing filter.

webrtc/modules/congestion_controller/probing_interval_estimator.cc

Index: webrtc/modules/congestion_controller/probing_interval_estimator.cc
diff --git a/webrtc/modules/congestion_controller/probing_interval_estimator.cc b/webrtc/modules/congestion_controller/probing_interval_estimator.cc
index 6e7a674ae8b4a5f7b182f19c88b547a9922ee82e..ed1134737e6dc3294fbd0e53a9fa044da6ee60ce 100644
--- a/webrtc/modules/congestion_controller/probing_interval_estimator.cc
+++ b/webrtc/modules/congestion_controller/probing_interval_estimator.cc
@@ -17,7 +17,6 @@
 
 namespace {
 constexpr int kMinIntervalMs = 2000;
-constexpr int kDefaultIntervalMs = 3000;
 constexpr int kMaxIntervalMs = 50000;
 }
 
@@ -25,31 +24,27 @@
     const AimdRateControl* aimd_rate_control)
     : ProbingIntervalEstimator(kMinIntervalMs,
                                kMaxIntervalMs,
-                               kDefaultIntervalMs,
                                aimd_rate_control) {}
 
 ProbingIntervalEstimator::ProbingIntervalEstimator(
-    int64_t min_interval_ms,
-    int64_t max_interval_ms,
-    int64_t default_interval_ms,
+    int min_interval_ms,
+    int max_interval_ms,
     const AimdRateControl* aimd_rate_control)
     : min_interval_ms_(min_interval_ms),
       max_interval_ms_(max_interval_ms),
-      default_interval_ms_(default_interval_ms),
       aimd_rate_control_(aimd_rate_control) {}
 
-int64_t ProbingIntervalEstimator::GetIntervalMs() const {
+rtc::Optional<int> ProbingIntervalEstimator::GetIntervalMs() const {
   rtc::Optional<int> bitrate_drop =
       aimd_rate_control_->GetLastBitrateDecreaseBps();
   int increase_rate = aimd_rate_control_->GetNearMaxIncreaseRateBps();
 
   if (!bitrate_drop || increase_rate <= 0)
-    return default_interval_ms_;
+    return rtc::Optional<int>();
 
-  return std::min(
+  return rtc::Optional<int>(std::min(
       max_interval_ms_,
-      std::max(static_cast<int64_t>(1000 * (*bitrate_drop) / increase_rate),
-               min_interval_ms_));
+      std::max(1000 * (*bitrate_drop) / increase_rate, min_interval_ms_)));
 }
 
 }  // namespace webrtc