GitLab

Logs a subset of the stack backtrace from the point of -dealloc into a
breakpad key to help debug messages to CrZombie objects.  This
productionizes the basic approach taken to debug a few recent zombie
object crashes.

BUG=none
TEST=monitor crash server.

Review URL: http://codereview.chromium.org/7766013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@98858 0039d316-1c4b-4281-b951-d872f2087c98