Delete unused methods of the VideoProcessing class. And fix a typo.

webrtc/modules/video_processing/video_processing_impl.h

Index: webrtc/modules/video_processing/video_processing_impl.h
diff --git a/webrtc/modules/video_processing/video_processing_impl.h b/webrtc/modules/video_processing/video_processing_impl.h
index 1d9a3775cf1d6682366fdb989b951ef23d955cfa..d098c9a0e0f37e4c40bd01a6f59dd72e1a5d350e 100644
--- a/webrtc/modules/video_processing/video_processing_impl.h
+++ b/webrtc/modules/video_processing/video_processing_impl.h
@@ -13,8 +13,6 @@
 
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/modules/video_processing/include/video_processing.h"
-#include "webrtc/modules/video_processing/brightness_detection.h"
-#include "webrtc/modules/video_processing/deflickering.h"
 #include "webrtc/modules/video_processing/frame_preprocessor.h"
 
 namespace webrtc {
@@ -26,9 +24,6 @@ class VideoProcessingImpl : public VideoProcessing {
   ~VideoProcessingImpl() override;
 
   // Implements VideoProcessing.
-  int32_t Deflickering(VideoFrame* frame, FrameStats* stats) override;
-  int32_t BrightnessDetection(const VideoFrame& frame,
-                              const FrameStats& stats) override;
   void EnableTemporalDecimation(bool enable) override;
   void SetInputFrameResampleMode(VideoFrameResampling resampling_mode) override;
   void EnableContentAnalysis(bool enable) override;
@@ -39,15 +34,13 @@ class VideoProcessingImpl : public VideoProcessing {
   uint32_t GetDecimatedFrameRate() override;
   uint32_t GetDecimatedWidth() const override;
   uint32_t GetDecimatedHeight() const override;
-  void EnableDenosing(bool enable) override;
+  void EnableDenoising(bool enable) override;
   const VideoFrame* PreprocessFrame(const VideoFrame& frame) override;
   VideoContentMetrics* GetContentMetrics() const override;
 
  private:
   rtc::CriticalSection mutex_;
-  VPMDeflickering deflickering_ GUARDED_BY(mutex_);
-  VPMBrightnessDetection brightness_detection_;
-  VPMFramePreprocessor frame_pre_processor_;
+  VPMFramePreprocessor frame_pre_processor_ GUARDED_BY(mutex_);
 };
 
 }  // namespace webrtc