GitLab

Sending the very same tab entity is wasteful: in most cases it will be
caught by other layers (which will realize the proto is identical) but
let's detect it in early stages, which also avoids unnecessary I/O to
disk.

Bug: 854493
Change-Id: Ia2ceaa4347bdf4dca1c5d0995b2466d07b41261a
Reviewed-on: https://chromium-review.googlesource.com/1107060Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568788}