Add a null pointer check for transaction_ in ContinueDespiteLastError.  The URL request job may have been cancelled but not yet deleted.
Add a null pointer check for transaction_ in
ContinueDespiteLastError.  The URL request job may have
been cancelled but not yet deleted.

R=eroman,jcampan
BUG=6423
Review URL: http://codereview.chromium.org/20146

git-svn-id: http://src.chromium.org/svn/trunk/src@9358 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: e5fea43f0e5b744d9d87d1f4bc8b2af85a005e5d
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