Refactor how padding is calculated.

webrtc/video/video_send_stream.h

Index: webrtc/video/video_send_stream.h
diff --git a/webrtc/video/video_send_stream.h b/webrtc/video/video_send_stream.h
index df3e3c4c638d99408d87075bdf2ffba4c05b9575..05f254d06b6d4aeeae217ae1de0f36e808f2c630 100644
--- a/webrtc/video/video_send_stream.h
+++ b/webrtc/video/video_send_stream.h
@@ -52,7 +52,7 @@ class VideoSendStream : public webrtc::VideoSendStream,
                         public webrtc::CpuOveruseObserver,
                         public webrtc::BitrateAllocatorObserver,
                         public webrtc::VCMProtectionCallback,
-                        protected webrtc::EncodedImageCallback {
+                        public EncodedImageCallback {
  public:
   VideoSendStream(int num_cpu_cores,
                   ProcessThread* module_process_thread,
@@ -103,8 +103,7 @@ class VideoSendStream : public webrtc::VideoSendStream,
  private:
   struct EncoderSettings {
     VideoCodec video_codec;
-    int min_transmit_bitrate_bps;
-    std::vector<VideoStream> streams;
+    VideoEncoderConfig config;
   };
 
   // Implements EncodedImageCallback. The implementation routes encoded frames
@@ -139,8 +138,11 @@ class VideoSendStream : public webrtc::VideoSendStream,
   rtc::Event encoder_wakeup_event_;
   volatile int stop_encoder_thread_;
   rtc::CriticalSection encoder_settings_crit_;
-  rtc::Optional<EncoderSettings> pending_encoder_settings_
+  std::unique_ptr<EncoderSettings> pending_encoder_settings_
       GUARDED_BY(encoder_settings_crit_);
+  // Only used on the encoder thread.
+  bool send_stream_registered_as_observer_;
+  std::unique_ptr<EncoderSettings> current_encoder_settings_;
 
   OveruseFrameDetector overuse_detector_;
   ViEEncoder vie_encoder_;