GitLab

Very minor cleanup. Switching to initializing extensions_delegate_
in the class member initialization section instead of the constructor
body.

Bug: None
Change-Id: I439d3ef34832d9c883f0c9cf0d92df8fbc378d0f
Reviewed-on: https://chromium-review.googlesource.com/1076685Reviewed-by: Mike Pinkerton <pinkerton@chromium.org>
Commit-Queue: Chris Mumford <cmumford@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562589}