Don't consider browsing contexts with empty names for named lookup.

TBR=dcheng@chromium.org

(cherry picked from commit 0c236612e5b506d3b1e3ab9b75b3a355e2ba620f)

Bug: 803620
Change-Id: I6c28067a10d812faf815a04360a701aee741abc5
Reviewed-on: https://chromium-review.googlesource.com/925541
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#537735}
Reviewed-on: https://chromium-review.googlesource.com/932912
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#557}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
3 files changed