GitLab

We need to implement a couple WebContentsDelegate functions in order to
enable fullscreen behaviours

Bug: b/128926264
Test: desktop cast_shell build w/ embedded video page
Change-Id: I7c5e95fb4f59b3369b35f770dcccff647bf7f899
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1585104Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Commit-Queue: Alex Sakhartchouk <alexst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662622}