Support cross-origin XMLHttpRequest loads and redirects for custom standard schemes when enabled via the cross-origin whitelist (issue #950).
- Call WebSecurityPolicy::registerURLSchemeAsCORSEnabled() for custom standard schemes.
- Explicitly check the cross-origin whitelist in CefResourceDispatcherHostDelegate::OnRequestRedirected() and add the appropriate CORS headers.
- Improve the CefAddCrossOriginWhitelistEntry() documentation to mention the top-level domain requirement for sub-domain matching.

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk/cef3@1235 5089003a-bbd8-11dd-ad1f-f1f9622dbc98