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

webrtc/modules/video_processing/brightness_detection.h

-/*
- *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_MODULES_VIDEO_PROCESSING_BRIGHTNESS_DETECTION_H_
-#define WEBRTC_MODULES_VIDEO_PROCESSING_BRIGHTNESS_DETECTION_H_
-
-#include "webrtc/modules/video_processing/include/video_processing.h"
-#include "webrtc/typedefs.h"
-
-namespace webrtc {
-
-class VPMBrightnessDetection {
- public:
-  VPMBrightnessDetection();
-  ~VPMBrightnessDetection();
-
-  void Reset();
-  int32_t ProcessFrame(const VideoFrame& frame,
-                       const VideoProcessing::FrameStats& stats);
-
- private:
-  uint32_t frame_cnt_bright_;
-  uint32_t frame_cnt_dark_;
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_VIDEO_PROCESSING_BRIGHTNESS_DETECTION_H_