BUG=9094
BUG=9094

GetRequestContextForMedia() in ProfileImpl and OffTheRecordProfileImpl
now respect --disk-cache-dir. Since the snippet for getting the path
from --disk-cache-dir is very short, it's not necessary to keep it in
a separate method so I duplicated the snippet and used it in both
classes.

Review URL: http://codereview.chromium.org/42517

git-svn-id: http://src.chromium.org/svn/trunk/src@12298 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: a301f3e74d199065a6bbf64f939690f4578ceac7
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