Avoid having two different WriteTransaction in ::syncer

There is a ::syncer::WriteTransaction so importing
::syncer::syncable::WriteTransaction into ::syncer with a "using"
statement causes ambiguity in a jumbo build.

Bug: 869381
Change-Id: Ie8a1130f448a26867d3240d4c6ec46d3cb712346
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1524346
Reviewed-by: Tatiana Gornak <melandory@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#643826}
2 files changed