Feature request: Add support for notification of changes to [dir] on <html> and <body> #5761
Description
As specified in guides/bidirectionality.md regarding change property of Directionality:
It will not emit for changes to dir on and , as these are assumed to be static.
I'm not sure that this is a correct assumption to make, since overlayed items(div.cdk-overlay-container) are generated outside the Angular application context, so currently we don't have a single point to change the layout of the application. And since overlayed items, like dialogs, do represent integral parts of an application, I believe that it should be possible to notify these components of changes to dir on <html> and <body> using the same Directionality feature, since these nodes are the only common ancestors of both div.cdk-overlay-container and Angular application context.
Since @jelbourn in his comment said that this is something that could potentially change in a subsequent iteration, I decided to open this feature request for a discussion.