Move cookies tree model helper code into cookies_tree_model_util.

So that the logic could be reused for the upcoming cookie prompt webui.

BUG=chromium-os:8134
TEST=Verify this CL does not break the cookies view in settings UI.  Don't verify chromium-os:8134 yet as the change for it depends on this CL.

Review URL: http://codereview.chromium.org/6611030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@77168 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed