Fix a screen capture issue on retina macOS devices.

webrtc/modules/desktop_capture/screen_capturer_mac.mm

 /*
  *  Copyright (c) 2013 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.
  */
 
@@ skipping 973 matching lines @@
   display_stream_manager_->UnregisterActiveStreams();
 }
 
 void ScreenCapturerMac::ScreenRefresh(CGRectCount count,
                                       const CGRect* rect_array) {
   if (screen_pixel_bounds_.is_empty())
     ScreenConfigurationChanged();
 
   DesktopRegion region;
   for (CGRectCount i = 0; i < count; ++i) {
-    // Convert from Density-Independent Pixel to physical pixel coordinates.
-    DesktopRect rect = ScaleAndRoundCGRect(rect_array[i], dip_to_pixel_scale_);
+    // All rects are already in physical pixel coordinates.
+    DesktopRect rect = DesktopRect::MakeXYWH(
+        rect_array[i].origin.x, rect_array[i].origin.y,
+        rect_array[i].size.width, rect_array[i].size.height);
     region.AddRect(rect);
   }
 
   helper_.InvalidateRegion(region);
 }
 
 std::unique_ptr<DesktopFrame> ScreenCapturerMac::CreateFrame() {
   std::unique_ptr<DesktopFrame> frame(
       new BasicDesktopFrame(screen_pixel_bounds_.size()));
   frame->set_dpi(DesktopVector(kStandardDPI * dip_to_pixel_scale_,
@@ skipping 12 matching lines @@
   std::unique_ptr<ScreenCapturerMac> capturer(
       new ScreenCapturerMac(options.configuration_monitor()));
   if (!capturer.get()->Init()) {
     return nullptr;
   }
 
   return capturer;
 }
 
 }  // namespace webrtc