This enables linter checking for "readability/namespace" violations
during presubmit and instead marks the few known exceptions that we
allow explicitly.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1371083003

Cr-Commit-Position: refs/heads/master@{#31019}

BUG=none
R=jkummerow@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/316133002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21693 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/259183002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@21035 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/129813008

Patch from Cosmin Truta <ctruta@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19738 ce2b1a6d-e550-0410-aec6-3dcde31c8c00