Migrate modules/video_coding to webrtc::Mutex.

Bug: webrtc:11567
Change-Id: I8023fbe7595f7ba8ae7c7db3583fc2e560ec3df2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/178803
Commit-Queue: Markus Handell <handellm@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31644}
diff --git a/modules/video_coding/fec_controller_default.cc b/modules/video_coding/fec_controller_default.cc
index 97919f5..827c853 100644
--- a/modules/video_coding/fec_controller_default.cc
+++ b/modules/video_coding/fec_controller_default.cc
@@ -20,7 +20,6 @@
 #include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
-using rtc::CritScope;
 
 const float kProtectionOverheadRateThreshold = 0.5;
 
@@ -54,7 +53,7 @@
                                            size_t height,
                                            size_t num_temporal_layers,
                                            size_t max_payload_size) {
-  CritScope lock(&crit_sect_);
+  MutexLock lock(&mutex_);
   loss_prot_logic_->UpdateFrameSize(width, height);
   loss_prot_logic_->UpdateNumLayers(num_temporal_layers);
   max_payload_size_ = max_payload_size;
@@ -94,7 +93,7 @@
   FecProtectionParams delta_fec_params;
   FecProtectionParams key_fec_params;
   {
-    CritScope lock(&crit_sect_);
+    MutexLock lock(&mutex_);
     loss_prot_logic_->UpdateBitRate(target_bitrate_kbps);
     loss_prot_logic_->UpdateRtt(round_trip_time_ms);
     // Update frame rate for the loss protection logic class: frame rate should
@@ -175,7 +174,7 @@
   } else if (enable_fec) {
     method = media_optimization::kFec;
   }
-  CritScope lock(&crit_sect_);
+  MutexLock lock(&mutex_);
   loss_prot_logic_->SetMethod(method);
 }
 
@@ -183,7 +182,7 @@
     const size_t encoded_image_length,
     const VideoFrameType encoded_image_frametype) {
   const size_t encoded_length = encoded_image_length;
-  CritScope lock(&crit_sect_);
+  MutexLock lock(&mutex_);
   if (encoded_length > 0) {
     const bool delta_frame =
         encoded_image_frametype != VideoFrameType::kVideoFrameKey;