Revert 257164 &quotRefactor ui::Clipboard::ObjectMap sanitization in...&quot

      Compile failure on several webkit bots: 

One example: http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Builder/builds/78865

> Refactor ui::Clipboard::ObjectMap sanitization in ClipboardMsgFilter.
> 
> BUG=352395
> R=tony@chromium.org
> TBR=creis@chromium.org
> 
> Review URL: https://codereview.chromium.org/200523004

TBR=dcheng@chromium.org

Review URL: https://codereview.chromium.org/200813002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257180 0039d316-1c4b-4281-b951-d872f2087c98