Broke layout tests userscripts/user-script-plugin-document.html and plugins/plugin-document-back-forward.html on all platforms.
> Removed static factories for data, ftp, file, and about jobs.
> Instead add corresponding ProtocolHandlers as needed.
> Remove URLRequestContext members used by these static
> factories. Bake FtpAuthCache into FtpProtocolHandler as it
> was already unique per FtpProtocolHandler.
> This is a revived version of http://crrev.com/10836206
>
> BUG=142945
>
>
> Review URL: https://chromiumcodereview.appspot.com/11931024TBR=pauljensen@chromium.org
Review URL: https://codereview.chromium.org/12605011
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@188927 0039d316-1c4b-4281-b951-d872f2087c98