Improve logging for UpdateActiveSimulcastLayers.

Bug: None
Change-Id: I56d14421044749e9bb89754a72a989820c025600
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/169220
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Rasmus Brandt <brandtr@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30620}
diff --git a/video/video_send_stream.cc b/video/video_send_stream.cc
index 8fae407..497db28 100644
--- a/video/video_send_stream.cc
+++ b/video/video_send_stream.cc
@@ -19,6 +19,7 @@
 #include "modules/rtp_rtcp/source/rtp_sender.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
 #include "rtc_base/task_utils/to_queued_task.h"
 #include "system_wrappers/include/clock.h"
 #include "system_wrappers/include/field_trial.h"
@@ -130,7 +131,23 @@
 void VideoSendStream::UpdateActiveSimulcastLayers(
     const std::vector<bool> active_layers) {
   RTC_DCHECK_RUN_ON(&thread_checker_);
-  RTC_LOG(LS_INFO) << "VideoSendStream::UpdateActiveSimulcastLayers";
+
+  rtc::StringBuilder active_layers_string;
+  active_layers_string << "{";
+  for (size_t i = 0; i < active_layers.size(); ++i) {
+    if (active_layers[i]) {
+      active_layers_string << "1";
+    } else {
+      active_layers_string << "0";
+    }
+    if (i < active_layers.size() - 1) {
+      active_layers_string << ", ";
+    }
+  }
+  active_layers_string << "}";
+  RTC_LOG(LS_INFO) << "UpdateActiveSimulcastLayers: "
+                   << active_layers_string.str();
+
   VideoSendStreamImpl* send_stream = send_stream_.get();
   worker_queue_->PostTask([this, send_stream, active_layers] {
     send_stream->UpdateActiveSimulcastLayers(active_layers);
diff --git a/video/video_send_stream_impl.cc b/video/video_send_stream_impl.cc
index 34ad748..d52f3ba 100644
--- a/video/video_send_stream_impl.cc
+++ b/video/video_send_stream_impl.cc
@@ -321,7 +321,6 @@
 void VideoSendStreamImpl::UpdateActiveSimulcastLayers(
     const std::vector<bool> active_layers) {
   RTC_DCHECK_RUN_ON(worker_queue_);
-  RTC_LOG(LS_INFO) << "VideoSendStream::UpdateActiveSimulcastLayers";
   bool previously_active = rtp_video_sender_->IsActive();
   rtp_video_sender_->SetActiveModules(active_layers);
   if (!rtp_video_sender_->IsActive() && previously_active) {