Fix detach with open()ed document leaving parent loading indefinitely

Change-Id: I26c2a054b9f1e5eb076acd677e1223058825f6d6

Bug: 803416
Test: fast/loader/document-open-iframe-then-detach.html
Change-Id: I26c2a054b9f1e5eb076acd677e1223058825f6d6
Reviewed-on: https://chromium-review.googlesource.com/887298
Reviewed-by: Mike West <mkwst@chromium.org>
Commit-Queue: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532967}
void DocumentLoader::ClearRedirectChain() {
  redirect_chain_.clear();
}

void DocumentLoader::ClearRedirectChain() {
  redirect_chain_.clear();
}
