modules/video_processing: refactor interface->include + more.

Moved/renamed:
webrtc/modules/video_processing/main/interface -> webrtc/modules/video_processing/include
webrtc/modules/video_processing/main/source/* -> webrtc/modules/video_processing
webrtc/modules/video_processing/main/test/unit_test -> webrtc/modules/video_processing/test

No downstream code seems to use this module.

BUG=webrtc:5095
TESTED=git cl try -c --bot=android_compile_rel --bot=linux_compile_rel --bot=win_compile_rel --bot=mac_compile_rel --bot=ios_rel --bot=linux_gn_rel --bot=win_x64_gn_rel --bot=mac_x64_gn_rel --bot=android_gn_rel -m tryserver.webrtc
R=pbos@webrtc.org, stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1410663004 .

Cr-Commit-Position: refs/heads/master@{#10697}

webrtc/modules/video_processing/brightness_detection.h

@@ -0,0 +1,35 @@
+/*
+ *  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 VideoProcessingModule::FrameStats& stats);
+
+ private:
+  uint32_t frame_cnt_bright_;
+  uint32_t frame_cnt_dark_;
+};
+
+}  // namespace webrtc
+
+#endif // WEBRTC_MODULES_VIDEO_PROCESSING_BRIGHTNESS_DETECTION_H_