Make shared memory segments writable only by their rightful owners.

BUG=143859
TEST=Chrome's UI still works on Linux and Chrome OS
Review URL: https://chromiumcodereview.appspot.com/10854242

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@158289 0039d316-1c4b-4281-b951-d872f2087c98
bool QueryRenderSupport(Display* dpy) {
  static bool render_supported = false;
  static bool render_supported_cached = false;

  if (render_supported_cached)
    return render_supported;

  int dummy;
  render_supported = XRenderQueryExtension(dpy, &dummy, &dummy);
  render_supported_cached = true;

  return render_supported;
}

bool QueryRenderSupport(Display* dpy) {
  static bool render_supported = false;
  static bool render_supported_cached = false;

  if (render_supported_cached)
    return render_supported;

  int dummy;
  render_supported = XRenderQueryExtension(dpy, &dummy, &dummy);
  render_supported_cached = true;

  return render_supported;
}
