Revert 256974 "Verify FormatType in ScopedClipboardWriter::Write..."

> Verify FormatType in ScopedClipboardWriter::WritePickledData.
> 
> BUG=352395
> R=tony@chromium.org
> TBR=sky@chromium.org
> 
> Review URL: https://codereview.chromium.org/199763002

TBR=dcheng@chromium.org

Review URL: https://codereview.chromium.org/199613003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256978 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256978