DesktopRect::UnionWith() to extend current rect to cover the input rect

webrtc/modules/desktop_capture/mac/desktop_configuration.mm

Index: webrtc/modules/desktop_capture/mac/desktop_configuration.mm
diff --git a/webrtc/modules/desktop_capture/mac/desktop_configuration.mm b/webrtc/modules/desktop_capture/mac/desktop_configuration.mm
index 4e227ca43d9d47d8e5dfbe04fc69974c07152579..c82d1cb631d68ee7370c7b28c3eb01936e0a9045 100644
--- a/webrtc/modules/desktop_capture/mac/desktop_configuration.mm
+++ b/webrtc/modules/desktop_capture/mac/desktop_configuration.mm
@@ -36,15 +36,6 @@ DesktopRect NSRectToDesktopRect(const NSRect& ns_rect) {
       static_cast<int>(ceil(ns_rect.origin.y + ns_rect.size.height)));
 }
 
-DesktopRect JoinRects(const DesktopRect& a,
-                              const DesktopRect& b) {
-  return DesktopRect::MakeLTRB(
-      std::min(a.left(), b.left()),
-      std::min(a.top(), b.top()),
-      std::max(a.right(), b.right()),
-      std::max(a.bottom(), b.bottom()));
-}
-
 // Inverts the position of |rect| from bottom-up coordinates to top-down,
 // relative to |bounds|.
 void InvertRectYOrigin(const DesktopRect& bounds,
@@ -148,10 +139,8 @@ MacDesktopConfiguration MacDesktopConfiguration::GetCurrent(Origin origin) {
     // display uses different DPI settings.
     if (display_config.dip_to_pixel_scale ==
         desktop_config.dip_to_pixel_scale) {
-      desktop_config.bounds =
-          JoinRects(desktop_config.bounds, display_config.bounds);
-      desktop_config.pixel_bounds =
-          JoinRects(desktop_config.pixel_bounds, display_config.pixel_bounds);
+      desktop_config.bounds.UnionWith(display_config.bounds);
+      desktop_config.pixel_bounds.UnionWith(display_config.pixel_bounds);
     }
   }