Revert 233759 "Make NativeTextfieldViews update the win system c..."

Caused new bug: http://crbug.com/320758

> Make NativeTextfieldViews update the win system caret.
> 
> Added a helper function to ui/base/win because we're
> going to need to do the same thing from content/browser.
> 
> BUG=142133
> 
> Review URL: https://codereview.chromium.org/61923005

TBR=dmazzoni@chromium.org
BUG=320758,142133

Review URL: https://codereview.chromium.org/77173004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236198 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236198