Disable getting share handles when PIX is enabled. PIX doesn't seem to work with share handles, so disable them when we detect that pix is enabled. BUG= TEST= Review URL: https://codereview.appspot.com/5625048 git-svn-id: https://angleproject.googlecode.com/svn/trunk@982 736b8ea6-26fd-11df-bfd4-992fa37f6226