Fixing memleak found by purify.
Fixing memleak found by purify.

This should fix leaks at:
extensions_service.cc:495 and 498
... and since the providers are getting cleaned up, it should take care of:
extensions_service.cc:211
... as well.

TBR=erikkay
TEST=Covered by automated tests.
BUG=None

Review URL: http://codereview.chromium.org/126037

git-svn-id: http://src.chromium.org/svn/trunk/src@18251 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: db6e03c5f613aac55fc32a12943c71e917049086
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser