Revert r224680: "Delete the omahaproxy-backed extension blacklist"

This broke the ASAN bots: http://build.chromium.org/p/chromium.memory/builders/Linux%20ASAN%20Tests%20%282%29/builds/17641/steps/unit_tests/logs/stdio

> Revert "LSan suppressions after r224680: `BlacklistTest.*`."
>
> This reverts commit 06bbf1b9dd714ca64d14d2deae758ae60968b8c9.
>
> Revert "Delete the omahaproxy-backed extension blacklist and clear its entries from the"
>
> This reverts commit e636c811a9d9814d39dd3842d6ee4516353fbd1f.

BUG=296828
TBR=kalman@chromium.org

Review URL: https://codereview.chromium.org/23497010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224702 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224702