Refactor how padding is calculated.

webrtc/modules/pacing/paced_sender.h

Index: webrtc/modules/pacing/paced_sender.h
diff --git a/webrtc/modules/pacing/paced_sender.h b/webrtc/modules/pacing/paced_sender.h
index 8879f12d0381abb7c9e6626dd897fb7eba03c9d2..5276e7a6788057d8080b734537b2a2374238237e 100644
--- a/webrtc/modules/pacing/paced_sender.h
+++ b/webrtc/modules/pacing/paced_sender.h
@@ -89,13 +89,15 @@ class PacedSender : public Module, public RtpPacketSender {
   // |bitrate_bps| * kDefaultPaceMultiplier.
   virtual void SetEstimatedBitrate(uint32_t bitrate_bps);
 
-  // Sets the bitrate that has been allocated for encoders.
+  // Sets the minimum send bitrate and maximum padding bitrate requested by send
+  // streams.
   // |allocated_bitrate| might be higher that the estimated available network
   // bitrate and if so, the pacer will send with |allocated_bitrate|.
-  // Padding packets will be utilized to reach |padding_bitrate| unless enough
-  // media packets are available.
+  // |max_padding_bitrate_bps| might be higher than the estimate available
+  // network bitrate and if so, the pacer will send padding packets to reach
+  // the min of the estimated available bitrate and |max_padding_bitrate_bps|.
   void SetAllocatedSendBitrate(int allocated_bitrate_bps,
-                               int padding_bitrate_bps);
+                               int max_padding_bitrate_bps);
 
   // Returns true if we send the packet now, else it will add the packet
   // information to the queue and call TimeToSendPacket when it's time to send.
@@ -157,6 +159,7 @@ class PacedSender : public Module, public RtpPacketSender {
   // order to meet pace time constraint).
   uint32_t estimated_bitrate_bps_ GUARDED_BY(critsect_);
   uint32_t min_send_bitrate_kbps_ GUARDED_BY(critsect_);
+  uint32_t max_padding_bitrate_kbps_ GUARDED_BY(critsect_);
   uint32_t pacing_bitrate_kbps_ GUARDED_BY(critsect_);
 
   int64_t time_last_update_us_ GUARDED_BY(critsect_);