GitLab

Extension options pages often have links to external pages as well as
internal extension pages. When embedded in an <extensionoptions> element
open external links in a new tab, and internal links in the embedded
view (unless specified otherwise).

BUG=386838

Review URL: https://codereview.chromium.org/471053003

Cr-Commit-Position: refs/heads/master@{#291241}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@291241 0039d316-1c4b-4281-b951-d872f2087c98