Only round back buffer to 64 pixels when vendor ID in Intel. This is actually to fix AMD / Intel switchable systems when using integrated Intel where the source rectangle to Present is not respected. Review URL: https://codereview.appspot.com/6459101 git-svn-id: https://angleproject.googlecode.com/svn/trunk@1254 736b8ea6-26fd-11df-bfd4-992fa37f6226