[Pkg-chromium-maint] Bug#844631: Still Present in 53.0.2785.143-1~deb8u1

[Jonathan Hutchins]

Note that the discussion at
https://bugs.chromium.org/p/chromium/issues/detail?id=664177 says the bug
is fixed in a build of 55, not 53, and further that 53 is insecure and
should not be used.