[Explore sites]: Add more horizontal spacing to tiles.

Bug: 894927,867488
Change-Id: I8c92aa6b3561aed2efd6332a0b1cd3ecde8cdb9b
Reviewed-on: https://chromium-review.googlesource.com/c/1277695
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Cathy Li <chili@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#599339}(cherry picked from commit 3eb4d6ca0ac677ba2dff5ae0670f79c2c4e7728f)
Reviewed-on: https://chromium-review.googlesource.com/c/1281048
Reviewed-by: Cathy Li <chili@chromium.org>
Cr-Commit-Position: refs/branch-heads/3578@{#23}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
2 files changed