Remove |running_| state from NackModule to avoid running a tight loop.

webrtc/modules/video_coding/nack_module.cc

Index: webrtc/modules/video_coding/nack_module.cc
diff --git a/webrtc/modules/video_coding/nack_module.cc b/webrtc/modules/video_coding/nack_module.cc
index d74f08952617da38ad7a7d75b7f87067021816a5..1bd88f0fc188e47df512916252cfd9ef4ff0e068 100644
--- a/webrtc/modules/video_coding/nack_module.cc
+++ b/webrtc/modules/video_coding/nack_module.cc
@@ -46,7 +46,6 @@ NackModule::NackModule(Clock* clock,
       nack_sender_(nack_sender),
       keyframe_request_sender_(keyframe_request_sender),
       reordering_histogram_(kNumReorderingBuckets, kMaxReorderedPackets),
-      running_(true),
       initialized_(false),
       rtt_ms_(kDefaultRttMs),
       newest_seq_num_(0),
@@ -58,8 +57,6 @@ NackModule::NackModule(Clock* clock,
 
 int NackModule::OnReceivedPacket(const VCMPacket& packet) {
   rtc::CritScope lock(&crit_);
-  if (!running_)
-    return -1;
   uint16_t seq_num = packet.seqNum;
   // TODO(philipel): When the packet includes information whether it is
   //                 retransmitted or not, use that value instead. For
@@ -132,21 +129,22 @@ void NackModule::Clear() {
   keyframe_list_.clear();
 }
 
-void NackModule::Stop() {
-  rtc::CritScope lock(&crit_);
-  running_ = false;
-}
-
 int64_t NackModule::TimeUntilNextProcess() {
-  rtc::CritScope lock(&crit_);
   return std::max<int64_t>(next_process_time_ms_ - clock_->TimeInMilliseconds(),
                            0);
 }
 
 void NackModule::Process() {
-  rtc::CritScope lock(&crit_);
-  if (!running_)
-    return;
+  if (nack_sender_) {
+    std::vector<uint16_t> nack_batch;
+    {
+      rtc::CritScope lock(&crit_);
+      nack_batch = GetNackBatch(kTimeOnly);
+    }
+
+    if (!nack_batch.empty())
+      nack_sender_->SendNack(nack_batch);
+  }
 
   // Update the next_process_time_ms_ in intervals to achieve
   // the targeted frequency over time. Also add multiple intervals
@@ -160,10 +158,6 @@ void NackModule::Process() {
                             (now_ms - next_process_time_ms_) /
                                 kProcessIntervalMs * kProcessIntervalMs;
   }
-
-  std::vector<uint16_t> nack_batch = GetNackBatch(kTimeOnly);
-  if (!nack_batch.empty() && nack_sender_ != nullptr)
-    nack_sender_->SendNack(nack_batch);
 }
 
 bool NackModule::RemovePacketsUntilKeyFrame() {