wstring: remove wstring version of SplitString

Retry of r84336.

BUG=23581

Review URL: http://codereview.chromium.org/6930047

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@84355 0039d316-1c4b-4281-b951-d872f2087c98
gfx::Font Label::GetDefaultFont() {
  return ResourceBundle::GetSharedInstance().GetFont(ResourceBundle::BaseFont);
}

gfx::Font Label::GetDefaultFont() {
  return ResourceBundle::GetSharedInstance().GetFont(ResourceBundle::BaseFont);
}
