Chromium is moving towards using C++11. Even more, it's going to require either gcc-4.8 or clang.
Distros like Ubuntu, Mageia, Fedora, openSUSE, Arch, CentOS, and Slackware are already using gcc-4.8 or later is their latest stable release.
On the other hand, Debian Wheezy (7.0) has gcc-4.7.2. Gentoo is using gcc-4.7.3 in stable.
I started a thread on gentoo-dev, gcc-4.8 may be needed in stable for www-client/chromium-38.x. There is a tracker for gcc-4.8 stabilization, bug #516152. There is also gcc-4.8 porting tracker, bug #461954.
Please consider testing gcc-4.8 on your stable Gentoo system, and file bugs for any package that fails to compile or needs to have a newer version stabilized to work with new gcc. I have recompiled all packages, the kernel, and GRUB without problems.
The title of this post is deliberately a bit similar to my earlier post Is your distro fast enough for Chromium? This browser project is pushing a lot towards shorter release cycles and latest software. I consider that a good thing. Now we just need to keep up with the updates, and any help is welcome.