Printing from Google web apps (Docs, Sheets, etc) saves to PDF instead of opening print dialog

[Brave-Matt]

Test plan

See brave/brave-core#2342

Description

Haven't run into this on any other sites, but when trying to print from Google Docs, Sheets, Slides ,etc, Brave offers to save this file as a PDF, rather than open the print dialog as expected. This happens with Shields up or down and can reproduced on Linux, macOS and Windows 10.

Steps to Reproduce

1. Visit google Sheets or any google app in Brave
2. Try to print sheet content to a home or office printer (or at all)
3. Follow the in-browser dialog, click Next

Actual result/Expected

Brave tries to save content as PDF//Should launch print system dialog

Reproduces how often:

Always

Brave version (brave://version info)

Happens on all Brave release channels
v0.60.48
v0.61.13
v0.63.4

Website problems only:

• Does the issue resolve itself when disabling Brave Shields? No
• Is the issue reproducible on the latest version of Chrome? No

Additional Information

2 users reporting:
https://community.brave.com/t/brave-browser-problem-google-sheets-internal-print-function-instead-of-opening-printer-downloads-sheet-automatically-as-pdf-bug/33193

[rebron]

cc: @fmarier pdfium related?

[simonhong]

I'm looking this.

[simonhong]

There is some difference between chrome and brave when click print button in docs.
After loading https://docs.google.com/presentation/d/1ou3qdnFhKdjR6gKZgDwx3YHDwVUF7y8eoqM3rhErMMQ/edit#slide=id.p, press print button.
Brave and chrome uses different request url.
Chrome: https://docs.google.com/presentation/d/1ou3qdnFhKdjR6gKZgDwx3YHDwVUF7y8eoqM3rhErMMQ/export/pdf?id=1ou3qdnFhKdjR6gKZgDwx3YHDwVUF7y8eoqM3rhErMMQ&pageid=p&attachment=false
Brave: https://docs.google.com/presentation/d/1ou3qdnFhKdjR6gKZgDwx3YHDwVUF7y8eoqM3rhErMMQ/export/pdf?id=1ou3qdnFhKdjR6gKZgDwx3YHDwVUF7y8eoqM3rhErMMQ&pageid=p

Brave doesn't have attachment=false query string. Who attach this additional query to docs url?
I think absence of this query leads downloading.

[simonhong]

I found the root cause of this issue.
Google web apps checks Chrome PDF Viewer from navigator.plugins list.

If list includes Chrome PDF Viewer, it attaches more query strings like attachment=false.
Brave doesn't have Chrome PDF Viewer plugin.

[simonhong]

Chromium build has same issue and fixed by changing plugin name from Chromium PDF Viewer to Chrome PDF Viewer in chrome/common/chrome_content_client_constants.cc.
So, I think absence of this plugin in brave caused this issue.

[btlechowski]

Verification passed on

Brave	0.68.113 Chromium: 76.0.3809.62 (Official Build) beta (64-bit)
Revision	7b77856b3aa34d72f246d12340fc1ded8b2c0e83-refs/branch-heads/3809@{#798}
OS	Windows 7 Service Pack 1 (Build 7601.24494)

Verified test plan from brave/brave-core#2342
PDF printed successfully.

Verification passed on

Brave	0.68.113 Chromium: 76.0.3809.62 (Official Build) beta (64-bit)
Revision	7b77856b3aa34d72f246d12340fc1ded8b2c0e83-refs/branch-heads/3809@{#798}
OS	Linux

• Verified print brings system print functionality instead of save file dialgoue

Verified passed with

Brave	0.68.114 Chromium: 76.0.3809.87 (Official Build) beta (64-bit)
Revision	111fe1e15d5ced26080a7dc239bcfe70f6c49aad-refs/branch-heads/3809@{#967}
OS	Mac OS X

• Verified test plan from Use pdfium brave-core#2342
• Verified STR from description, file was printed instead of being prompted to save a PDF.

[andrew-pyle]

Brave user here. I have been printing successfully from Google Sheets in Brave in past months, but today, this issue seems to be happening again.

Instead of opening the Print dialog window, after the Next button, I get a PDF save automatically. Maybe Chromium has made some changes here?

Brave requested this URL after clicking the Next button: https://docs.google.com/spreadsheets/u/1/d/{id-omitted here}/pdf?id={id-omitted here}.

Clicking this button usually brings up the chrome print dialog.

Mentioning @simonhong because he troubleshot this problem successfully last year.

[SneakyLeif]

I’m running into the same exact issue. The only way to print a Google Sheets doc to a printer is to first export as PDF, and then print the PDF. Printing the PDF works fine in Brave, though! Very annoying.

Brave version:
Version 1.14.84 Chromium: 85.0.4183.121 (Official Build) (64-bit)

[linuxturtle]

This issue is still happening for me with the latest build on Linux.

Version 1.35.103 Chromium: 98.0.4758.102 (Official Build) (64-bit)](https://brave.com/latest/)