Allow the content browser client to specify a special cookie store to be
used for a given render process id. This special cookie store will then
be used for renderer messages pertaining to cookies, url fetches in net,
and websockets. If the special cookie store is NULL, a default cookie store
will be used.

Re-submit of https://codereview.chromium.org/188693003

See https://codereview.chromium.org/188693003 for reviewers/lgtm's.

Review URL: https://codereview.chromium.org/197043005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256657 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256657