Code: void ChromeClientImpl::Focus() {
  if (web_view_->Client())
    web_view_->Client()->DidFocus();
 }

Vulnerability Type: 
CWE ID: 
Summary: A JavaScript focused window could overlap the fullscreen notification in Fullscreen in Google Chrome prior to 66.0.3359.117 allowed a remote attacker to obscure the full screen warning via a crafted HTML page.
Commit Message: If a page calls |window.focus()|, kick it out of fullscreen.

BUG=776418, 800056

Change-Id: I1880fe600e4814c073f247c43b1c1ac80c8fc017
Reviewed-on: https://chromium-review.googlesource.com/852378
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533790}