Revert of Set proper referrer for css resource fetching (https://codereview.chromium.org/239353007/)

Reason for revert:
Caused regression

Original issue's description:
> Set proper referrer for css resource fetching
> 
> Fetching css resources are initiated as follows:
>   - Create FetchRequest
>   - Call ResourceFetcher::fetchXXX()
> 
> git-grep shows me that CSSImageValue, CSSImageSetValue and
> CSSFontFaceSrcValue are all of the resource fetch initiators
> which live in css/. I think that setting referrer in these
> classes should cover all css resource fetching.
> 
> Since resource fetching is delayed until the resource is actually
> needed, we need to hold the referrer somewhere.
> This CL modifies the css parser to set referrer to corresponding
> CSSValue (CSSImageValue and CSSFontFaceSrcValue) when it sees url(...).
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=172433

Review URL: https://codereview.chromium.org/304603006

git-svn-id: svn://svn.chromium.org/blink/trunk@175004 bbb929c8-8fbe-4397-9dbb-9b2b20218538