Forward capturer_id between DesktopFrame and its implementations

webrtc/modules/desktop_capture/desktop_frame.cc

Index: webrtc/modules/desktop_capture/desktop_frame.cc
diff --git a/webrtc/modules/desktop_capture/desktop_frame.cc b/webrtc/modules/desktop_capture/desktop_frame.cc
index 12e4ed8a09abd022d777c2c6588f41a06da91981..1c3939b988244dfc8ea0c520d1456fd0b841fedf 100644
--- a/webrtc/modules/desktop_capture/desktop_frame.cc
+++ b/webrtc/modules/desktop_capture/desktop_frame.cc
@@ -76,6 +76,7 @@ DesktopFrame* BasicDesktopFrame::CopyOf(const DesktopFrame& frame) {
   }
   result->set_dpi(frame.dpi());
   result->set_capture_time_ms(frame.capture_time_ms());
+  result->set_capturer_id(frame.capturer_id());
   *result->mutable_updated_region() = frame.updated_region();
   return result;
 }