[mojo] include mojo header

https://chromium-review.googlesource.com/c/chromium/src/+/1447145

atom/browser/api/frame_subscriber.cc

@@ -10,6 +10,7 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
+#include "media/capture/mojom/video_capture_types.mojom.h"
 #include "ui/gfx/skbitmap_operations.h"
 
 #include "atom/common/node_includes.h"