Let ViEEncoder handle resolution changes.

webrtc/video/vie_encoder.h

Index: webrtc/video/vie_encoder.h
diff --git a/webrtc/video/vie_encoder.h b/webrtc/video/vie_encoder.h
index c534b5566caae4b7b5b49cca6bab7e9b0202bad2..4f5a5dd4d8e1ffd15dc235ed6b3b9bb2e5f4409f 100644
--- a/webrtc/video/vie_encoder.h
+++ b/webrtc/video/vie_encoder.h
@@ -99,11 +99,27 @@ class ViEEncoder : public rtc::VideoSinkInterface<VideoFrame>,
 
  private:
   class EncodeTask;
-  class VideoSourceProxy;
   class ConfigureEncoderTask;
+  class VideoSourceProxy;
+
+  struct VideoFrameInfo {
+    VideoFrameInfo(int width,
+                   int height,
+                   VideoRotation rotation,
+                   bool is_texture)
+        : width(width),
+          height(height),
+          rotation(rotation),
+          is_texture(is_texture) {}
+    int width;
+    int height;
+    webrtc::VideoRotation rotation;
+    bool is_texture;
+  };
 
   void ConfigureEncoderOnTaskQueue(VideoEncoderConfig config,
                                    size_t max_data_payload_length);
+  void ReconfigureEncoder();
 
   // Implements VideoSinkInterface.
   void OnFrame(const VideoFrame& video_frame) override;
@@ -138,7 +154,6 @@ class ViEEncoder : public rtc::VideoSinkInterface<VideoFrame>,
   const VideoSendStream::Config::EncoderSettings settings_;
   const VideoCodecType codec_type_;
 
-  const std::unique_ptr<VideoProcessing> vp_;
   vcm::VideoSender video_sender_ ACCESS_ON(&encoder_queue_);
 
   OveruseFrameDetector overuse_detector_ ACCESS_ON(&encoder_queue_);
@@ -159,7 +174,12 @@ class ViEEncoder : public rtc::VideoSinkInterface<VideoFrame>,
   std::unique_ptr<SimulcastRateAllocator> rate_allocator_
       ACCESS_ON(&encoder_queue_);
 
-  uint32_t encoder_start_bitrate_bps_ ACCESS_ON(&encoder_queue_);
+  // Set when ConfigureEncoder has been called in order to lazy reconfigure the
+  // encoder on the next frame.
+  bool pending_encoder_reconfiguration_ ACCESS_ON(&encoder_queue_);
+  rtc::Optional<VideoFrameInfo> last_frame_info_ ACCESS_ON(&encoder_queue_);
+
+  unsigned int encoder_start_bitrate_bps_ ACCESS_ON(&encoder_queue_);
   size_t max_data_payload_length_ ACCESS_ON(&encoder_queue_);
   uint32_t last_observed_bitrate_bps_ ACCESS_ON(&encoder_queue_);
   bool encoder_paused_and_dropped_frame_ ACCESS_ON(&encoder_queue_);