Mac: fix screen capture freezes when context menu popup in Chrome.

webrtc/modules/desktop_capture/screen_capturer_mac.mm

Index: webrtc/modules/desktop_capture/screen_capturer_mac.mm
diff --git a/webrtc/modules/desktop_capture/screen_capturer_mac.mm b/webrtc/modules/desktop_capture/screen_capturer_mac.mm
index b1d7c9048e91d3c482fc249eaa5db701b61279cc..6d13e5315982e43758752012da2e57410f658d19 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_mac.mm
+++ b/webrtc/modules/desktop_capture/screen_capturer_mac.mm
@@ -98,7 +98,7 @@ class DisplayStreamManager {
         CFRunLoopSourceRef source =
             CGDisplayStreamGetRunLoopSource(wrapper.stream);
         CFRunLoopRemoveSource(CFRunLoopGetCurrent(), source,
-                              kCFRunLoopDefaultMode);
+                              kCFRunLoopCommonModes);
         CGDisplayStreamStop(wrapper.stream);
       }
     }
@@ -972,7 +972,7 @@ bool ScreenCapturerMac::RegisterRefreshAndMoveHandlers() {
 
       CFRunLoopSourceRef source =
           CGDisplayStreamGetRunLoopSource(display_stream);
-      CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopDefaultMode);
+      CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopCommonModes);
       display_stream_manager_->SaveStream(unique_id, display_stream);
     }
   }