UserAgent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:51.0) Gecko/20100101 Firefox/51.0

Steps to reproduce the problem:
1. Executing the command "ninja -C out/Default chrome".

What is the expected behavior?
build complete.

What went wrong?
../../chrome/browser/ui/libgtkui/gtk_ui.cc:245:6: error: ‘void libgtkui::{anonymous}::PickButtonTintFromColors(SkColor, SkColor, SkColor, color_utils::HSL*)’ defined but not used [-Werror=unused-function]
 void PickButtonTintFromColors(SkColor accent_color,

Did this work before? N/A 

Chrome version: <Copy from: 'about:version'>  Channel: n/a
OS Version: 
Flash Version: