UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36

Steps to reproduce the problem:
1. Enable "Open PDF files in the default PDF viewer application" to prevent Chrome from opening PDF files directly
2. Right-click any link to a PDF and select 'save link as'

What is the expected behavior?
The file should download but NOT open. 

What went wrong?
The file opens in the system default PDF viewer.

Did this work before? Yes 54

Chrome version: 56.0.2924.87  Channel: stable
OS Version: 10.0
Flash Version: 

PDF files are perhaps the most risky file format. As such, there's absolutely no good reason to force them to either open it PDF files in Chrome (which has had its own major PDF security issues - see 53.0.2785.89 for examples), *or* force them to open it in third-party PDF viewers that each have had their own security issues.

Users need to be able to safely download PDF files and later decide whether they want to scan them for security issues or open the files on their own.