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
void SetDefaultX11ErrorHandlers() {
  SetX11ErrorHandlers(NULL, NULL);
}

void SetDefaultX11ErrorHandlers() {
  SetX11ErrorHandlers(NULL, NULL);
}
