One of the best parts of Gentoo for me is the community.
For example, I regularly receive email from people who volunteer to help with testing hard masked www-client/chromium ebuilds. FWIW you don't need to email me or the Gentoo Chromium team - just start testing and filing bugs. On the other hand, I do appreciate when people express interest in helping out.
Another example is helping with getting bugs resolved.
Bug #556812 looked rather mysterious - until Guillaume ZITTA found that "build" is a red herring, and in fact the "tracing" module being imported is a different one (from dev-python/tracing as opposed to chromium sources). It was an unfortunate names collision - once found, quite easy to fix.
In bug #553502 Johan Hovold found we need to require postproc USE flag for libvpx to avoid a crash.
See bug #551666 for some Alexey Dobriyan's gdb magic mostly based on a single line segfault report from dmesg...
These are just a few examples.
By the way, the area where we could use more help is arm architecture support. Some specific bugs where help is wanted are #555702, #545368, #520180, and #483130. Please report whether you can reproduce or not, post emerge --info from your system and the compressed build log in case build fails.