Add the method to check if offline archive is in internal dir

Bug: 758690
Change-Id: I8bb4283fc40a87fa7a87df2c7e513e2e16903290
Reviewed-on: https://chromium-review.googlesource.com/828049
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Commit-Queue: Jian Li <jianli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524232}
void OfflinePageModelImpl::DeletePendingArchiver(
    OfflinePageArchiver* archiver) {
  pending_archivers_.erase(
      std::find_if(pending_archivers_.begin(), pending_archivers_.end(),
                   [archiver](const std::unique_ptr<OfflinePageArchiver>& a) {
                     return a.get() == archiver;
                   }));
}

void OfflinePageModelImpl::DeletePendingArchiver(
    OfflinePageArchiver* archiver) {
  pending_archivers_.erase(
      std::find_if(pending_archivers_.begin(), pending_archivers_.end(),
                   [archiver](const std::unique_ptr<OfflinePageArchiver>& a) {
                     return a.get() == archiver;
                   }));
}
