Remove differ from ScreenCapturer implementations

webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.h

 /*
  *  Copyright (c) 2014 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_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_GDI_H_
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_GDI_H_
 
 #include <memory>
 
 #include "webrtc/modules/desktop_capture/screen_capturer.h"
 
 #include <windows.h>
 
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
-#include "webrtc/modules/desktop_capture/screen_capturer_helper.h"
 #include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
 #include "webrtc/modules/desktop_capture/win/scoped_thread_desktop.h"
 
 namespace webrtc {
 
-class Differ;
-
 // ScreenCapturerWinGdi captures 32bit RGB using GDI.
 //
 // ScreenCapturerWinGdi is double-buffered as required by ScreenCapturer.
+// This class does not detect DesktopFrame::updated_region(), the field is
+// always set to the entire frame rectangle. ScreenCapturerDifferWrapper should
+// be used if that functionality is necessary.
 class ScreenCapturerWinGdi : public ScreenCapturer {
  public:
   explicit ScreenCapturerWinGdi(const DesktopCaptureOptions& options);
   virtual ~ScreenCapturerWinGdi();
 
   // Overridden from ScreenCapturer:
   void Start(Callback* callback) override;
   void SetSharedMemoryFactory(
       std::unique_ptr<SharedMemoryFactory> shared_memory_factory) override;
   void Capture(const DesktopRegion& region) override;
@@ skipping 11 matching lines @@
   bool CaptureImage();
 
   // Capture the current cursor shape.
   void CaptureCursor();
 
   Callback* callback_ = nullptr;
   std::unique_ptr<SharedMemoryFactory> shared_memory_factory_;
   ScreenId current_screen_id_ = kFullDesktopScreenId;
   std::wstring current_device_key_;
 
-  // A thread-safe list of invalid rectangles, and the size of the most
-  // recently captured screen.
-  ScreenCapturerHelper helper_;
-
   ScopedThreadDesktop desktop_;
 
   // GDI resources used for screen capture.
   HDC desktop_dc_ = NULL;
   HDC memory_dc_ = NULL;
 
   // Queue of the frames buffers.
   ScreenCaptureFrameQueue<SharedDesktopFrame> queue_;
 
   // Rectangle describing the bounds of the desktop device context, relative to
   // the primary display's top-left.
   DesktopRect desktop_dc_rect_;
 
-  // Class to calculate the difference between two screen bitmaps.
-  std::unique_ptr<Differ> differ_;
-
   HMODULE dwmapi_library_ = NULL;
   DwmEnableCompositionFunc composition_func_ = nullptr;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(ScreenCapturerWinGdi);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_GDI_H_