GitLab

Set the owner_extension_id in GuestViewBase::Init so that it's available in request.embedderExtensionId in onEmbedRequested in the app to be embedded. This also simplifies code in GuestViewBase a bit.

BUG=444749
TBR=rockot@chromium.org for guest_view_internal_api.cc

Review URL: https://codereview.chromium.org/823543003

Cr-Commit-Position: refs/heads/master@{#309600}