Remove differ from ScreenCapturer implementations

webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
index e22b272d145ea3a4072adc027c20c325bf9e6427..e5a37c97d50d0b6526d836c8bcff070b9411a35b 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
@@ -18,7 +18,6 @@
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/desktop_frame_win.h"
 #include "webrtc/modules/desktop_capture/desktop_region.h"
-#include "webrtc/modules/desktop_capture/differ.h"
 #include "webrtc/modules/desktop_capture/mouse_cursor.h"
 #include "webrtc/modules/desktop_capture/win/cursor.h"
 #include "webrtc/modules/desktop_capture/win/desktop.h"
@@ -116,33 +115,12 @@ void ScreenCapturerWinMagnifier::Capture(const DesktopRegion& region) {
     return;
   }
 
-  const DesktopFrame* current_frame = queue_.current_frame();
-  const DesktopFrame* last_frame = queue_.previous_frame();
-  DesktopRegion updated_region;
-  if (last_frame && last_frame->size().equals(current_frame->size())) {
-    // Make sure the differencer is set up correctly for these previous and
-    // current screens.
-    if (!differ_.get() || (differ_->width() != current_frame->size().width()) ||
-        (differ_->height() != current_frame->size().height()) ||
-        (differ_->bytes_per_row() != current_frame->stride())) {
-      differ_.reset(new Differ(current_frame->size().width(),
-                               current_frame->size().height(),
-                               DesktopFrame::kBytesPerPixel,
-                               current_frame->stride()));
-    }
-
-    // Calculate difference between the two last captured frames.
-    differ_->CalcDirtyRegion(
-        last_frame->data(), current_frame->data(), &updated_region);
-  } else {
-    updated_region.SetRect(DesktopRect::MakeSize(current_frame->size()));
-  }
-
   // Emit the current frame.
   std::unique_ptr<DesktopFrame> frame = queue_.current_frame()->Share();
   frame->set_dpi(DesktopVector(GetDeviceCaps(desktop_dc_, LOGPIXELSX),
                                GetDeviceCaps(desktop_dc_, LOGPIXELSY)));
-  frame->mutable_updated_region()->Swap(&updated_region);
+  frame->mutable_updated_region()->SetRect(
+      DesktopRect::MakeSize(frame->size()));
   frame->set_capture_time_ms((rtc::TimeNanos() - capture_start_time_nanos) /
                              rtc::kNumNanosecsPerMillisec);
   callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));