Looks like RenderWidgetHostViewAura::RequiresDoubleTapGestureEvents() would return the wrong thing (always false) for any child local root, it only does the right thing when there is an owner delegate on the RenderWidgetHost, which implies the RenderWidget is for the main frame.

Where would we track that followup work?

bool RenderWidgetHostViewAura::RequiresDoubleTapGestureEvents() const {
  RenderViewHost* rvh = RenderViewHost::From(host());
  return rvh && rvh->GetWebkitPreferences().double_tap_to_zoom_enabled;
}
 

Looks like RenderWidgetHostViewAura::RequiresDoubleTapGestureEvents() would return the wrong thing (always false) for any child local root, it only does the right thing when there is an owner delegate on the RenderWidgetHost, which implies the RenderWidget is for the main frame.

bool RenderWidgetHostViewAura::RequiresDoubleTapGestureEvents() const {
  RenderViewHost* rvh = RenderViewHost::From(host());
  return rvh && rvh->GetWebkitPreferences().double_tap_to_zoom_enabled;
}

(From 822455)