1917688 - [meta] Support client-side printing in Google Slides

Status: NEW

(Core :: Printing: Setup, enhancement)

Description

[Daniel Holbert [:dholbert]]

[Spinning this off for followup work from bug 1521655, for one part of gsuite / Google Workspace where our printing behavior hasn't yet changed]

STR:

1. Visit some Google Slides presentation, e.g. this one I just created:
   https://docs.google.com/presentation/d/1kVjcMffbgARYzPLEpcdiK7CqrjKIdtNZF0nSRGUD5H4/edit
2. Try to print, using Ctrl+P (or Cmd+P on macOS), or using the in-page "File" menu, "Print" menu-item.

ACTUAL RESULTS:
For now, Google Slides handles this operation by generating a PDF and opening it in a new tab (which can then be printed if the user does Ctrl+P again).

EXPECTED RESULTS:
Browser's own native print dialog should appear (this is what happens in Chrome).

We should check in with the Google Workspace folks to see what (if any) features/bugs they might be blocked on from us to get this enabled.

Comment 1

[Daniel Holbert [:dholbert]]

I discussed this a bit with a contact from Google over email. Summing that up, the situation right now is as follows:

• Google Slides client-side printing works in Chrome by generating a server-side PDF, and then loading that PDF in a hidden iframe (as a blob URI), and then invoking window.print() on that iframe's window object from the outer document when the iframe is loaded.
• Google folks observed that they don't have visibility into PDFs-loaded-in-iframes (see bug 1376151 comment 2 for more on this); it's cross-origin.
• However, Google folks should still be able to observe the load event and fire window.print when that happens, as of bug 1618553.

So I think this should be workable.