Set parent for window picker dialog on Mac

chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm

Index: chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm b/chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm
index 1b31516cb83eb18f43b056a352cd4784db491a5f..19eade711ffaf2cb50674a790281100043c03291 100644
--- a/chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm
+++ b/chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm
@@ -19,6 +19,7 @@ void DesktopMediaPickerCocoa::Show(gfx::NativeWindow context,
                                    const DoneCallback& done_callback) {
   controller_.reset(
       [[DesktopMediaPickerController alloc] initWithMediaList:media_list.Pass()
+                                                       parent:parent
                                                      callback:done_callback
                                                       appName:app_name]);
   [controller_ showWindow:nil];