/usr/share/pixmaps/chromium.png is in chromium 70.0.3538.110-1~deb9u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/pixmaps/../icons/hicolor/48x48/apps/chromium.png
/usr/share/pixmaps/../icons/hicolor/48x48/apps/chromium.png