If the plugins setting is managed and can't be controlled by the user, then disable the run all plugins link on the plugins settings bubble.

BUG=321772

Review URL: https://codereview.chromium.org/126143002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243639 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243639