Move more calls to webrtc::field_trial::FindFullName into ctor

webrtc/video/video_send_stream.cc

Index: webrtc/video/video_send_stream.cc
diff --git a/webrtc/video/video_send_stream.cc b/webrtc/video/video_send_stream.cc
index 9189b98e5a2855b682887bda76737723454c1edd..a207b19b984506507f52ce0f92ab0a9f9e0f14c3 100644
--- a/webrtc/video/video_send_stream.cc
+++ b/webrtc/video/video_send_stream.cc
@@ -289,17 +289,6 @@ int CalculateMaxPadBitrateBps(std::vector<VideoStream> streams,
   return pad_up_to_bitrate_bps;
 }
 
-uint32_t CalculateOverheadRateBps(int packets_per_second,
-                                  size_t overhead_bytes_per_packet,
-                                  uint32_t max_overhead_bps) {
-  if (webrtc::field_trial::FindFullName("WebRTC-SendSideBwe-WithOverhead") !=
-      "Enabled")
-    return 0;
-  uint32_t overhead_bps =
-      static_cast<uint32_t>(8 * overhead_bytes_per_packet * packets_per_second);
-  return std::min(overhead_bps, max_overhead_bps);
-}
-
 int CalculatePacketRate(uint32_t bitrate_bps, size_t packet_size_bytes) {
   size_t packet_size_bits = 8 * packet_size_bytes;
   // Ceil for int value of bitrate_bps / packet_size_bits.
@@ -398,6 +387,12 @@ class VideoSendStreamImpl : public webrtc::BitrateAllocatorObserver,
   void SignalEncoderTimedOut();
   void SignalEncoderActive();
 
+  uint32_t CalculateOverheadRateBps(int packets_per_second,
+                                    size_t overhead_bytes_per_packet,

[minyue-webrtc, 2017/01/31 11:48:06]

Feels better if we keep it outside but add send_side_bwe_with_overhead as an
arg. Because it is a utility function (given all private vars, it is still
unable to calculate overhead rate)

+                                    uint32_t max_overhead_bps);
+
+  const bool send_side_bwe_with_overhead_;
+
   SendStatisticsProxy* const stats_proxy_;
   const VideoSendStream::Config* const config_;
   std::map<uint32_t, RtpState> suspended_ssrcs_;
@@ -758,7 +753,9 @@ VideoSendStreamImpl::VideoSendStreamImpl(
     const VideoSendStream::Config* config,
     int initial_encoder_max_bitrate,
     std::map<uint32_t, RtpState> suspended_ssrcs)
-    : stats_proxy_(stats_proxy),
+    : send_side_bwe_with_overhead_(webrtc::field_trial::FindFullName(
+            "WebRTC-SendSideBwe-WithOverhead") == "Enabled"),
+      stats_proxy_(stats_proxy),
       config_(config),
       suspended_ssrcs_(std::move(suspended_ssrcs)),
       module_process_thread_(nullptr),
@@ -978,6 +975,17 @@ void VideoSendStreamImpl::SignalEncoderActive() {
       max_padding_bitrate_, !config_->suspend_below_min_bitrate);
 }
 
+uint32_t VideoSendStreamImpl::CalculateOverheadRateBps(
+    int packets_per_second,
+    size_t overhead_bytes_per_packet,
+    uint32_t max_overhead_bps) {
+  if (!send_side_bwe_with_overhead_)
+    return 0;
+  uint32_t overhead_bps =
+      static_cast<uint32_t>(8 * overhead_bytes_per_packet * packets_per_second);
+  return std::min(overhead_bps, max_overhead_bps);
+}
+
 void VideoSendStreamImpl::OnEncoderConfigurationChanged(
     std::vector<VideoStream> streams,
     int min_transmit_bitrate_bps) {