Move usage of QualityScaler to ViEEncoder.

webrtc/media/engine/videoencodersoftwarefallbackwrapper.h

Index: webrtc/media/engine/videoencodersoftwarefallbackwrapper.h
diff --git a/webrtc/media/engine/videoencodersoftwarefallbackwrapper.h b/webrtc/media/engine/videoencodersoftwarefallbackwrapper.h
index 05e815df46954f7cedd347edac3e8c2d980dd2a1..3d53090a27f5687b836f9e9686b7b013949165e7 100644
--- a/webrtc/media/engine/videoencodersoftwarefallbackwrapper.h
+++ b/webrtc/media/engine/videoencodersoftwarefallbackwrapper.h
@@ -42,8 +42,8 @@ class VideoEncoderSoftwareFallbackWrapper : public VideoEncoder {
   int32_t SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
   int32_t SetRateAllocation(const BitrateAllocation& bitrate_allocation,
                             uint32_t framerate) override;
-  void OnDroppedFrame() override;
   bool SupportsNativeHandle() const override;
+  ScalingSettings GetScalingSettings() const override;
 
  private:
   bool InitFallbackEncoder();