GitLab

BUG=430096
TBR=nasko@chromium.org for render_widget_host_view_guest.*
TBR=kenrb@chromium.org for browser_plugin_messages.h
TBR=lazyboy@chromium.org for overall.

Review URL: https://codereview.chromium.org/690263003

Cr-Commit-Position: refs/heads/master@{#302623}