Revert 175890: actually, looks like we want this to also help move chromeos webui pages out of src/…

Revert 175890: actually, looks like we want this to also help move chromeos webui pages out of src/chrome.
> Revert 175822
> 
> After more investigation of what it would take to share the webui code framework from chrome with content, it didn't seam feasible to do this. The code in chrome (i.e. ChromeURLDataManager) is heavily tied to chrome, and is used by chrome for non-webui stuff. The JS code is also specific to Chrome. It seems better to not bring in all this stuff to content.
> 
> > Allow multiple WebUIControllerFactory objects to be registered. This makes is possible to implement webui inside content.
> > Review URL: https://codereview.chromium.org/11783038
> 
> TBR=jam@chromium.org
> Review URL: https://codereview.chromium.org/11818036

TBR=jam@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=175971