Use unique processes for data URLs on restore.

Data URLs are usually put into the process that created them, but this
info is not tracked after a tab restore.  Ensure that they do not end up
in the parent frame's process (or each other's process), in case they
are malicious.

BUG=863069

Change-Id: Ib391f90c7bdf28a0a9c057c5cc7918c10aed968b
Reviewed-on: https://chromium-review.googlesource.com/1150767
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Charlie Reis <creis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581023}
void SiteInstanceImpl::PreventAssociationWithSpareProcess() {
  can_associate_with_spare_process_ = false;
}

void SiteInstanceImpl::PreventAssociationWithSpareProcess() {
  can_associate_with_spare_process_ = false;
}
