UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36

Steps to reproduce the problem:
The --screenshot flag currently only takes an screenshot of the content rendered according to the window size

What is the expected behavior?
Be able to specify Height, Width if nothing is specified then return an screenshot for the full width/height of the page

What went wrong?
Currently there is fixed width/height for the --screenshot option for the headless build 

Did this work before? N/A 

Chrome version: 50.0.2661.102  Channel: n/a
OS Version: OS X 10.11.3
Flash Version: Shockwave Flash 21.0 r0