Don't try to close first-navigation tabs when showing the supervised user interstitial inside a <we…

Don't try to close first-navigation tabs when showing the supervised user interstitial inside a <webview>.

A WebContents in a <webview> is under the control of the embedding page, so we
can't simply close it (and there isn't a browser or tab strip for it anyway).

BUG=545394
Committed: https://crrev.com/34f34c5fe939d8520e5ce59cc31e11cc4b439e75
Cr-Commit-Position: refs/heads/master@{#355300}

[Bernhard Bauer, 2015-10-21 14:10:18]

bauerb@chromium.org changed reviewers:
+ treib@chromium.org

[Bernhard Bauer, 2015-10-21 14:10:19]

Please review. Thanks!

[Bernhard Bauer, 2015-10-21 14:22:32]

Sorry, had to rewrite this to compile Android, and doing the check inline was
getting ugly.

[Marc Treib, 2015-10-21 14:37:54]

LGTM
(Somehow, "close this tab if it has no history" is getting *way* more
complicated than it should be...)

[Bernhard Bauer, 2015-10-21 14:59:04]

On 2015/10/21 14:37:54, Marc Treib wrote:
> LGTM
> (Somehow, "close this tab if it has no history" is getting *way* more
> complicated than it should be...)

Word.

[Bernhard Bauer, 2015-10-21 14:59:09]

The CQ bit was checked by bauerb@chromium.org

[commit-bot: I haz the power, 2015-10-21 14:59:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1417813004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1417813004/40001

[commit-bot: I haz the power, 2015-10-21 15:38:38]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-10-21 15:39:23]

Patchset 3 (id:??) landed as
https://crrev.com/34f34c5fe939d8520e5ce59cc31e11cc4b439e75
Cr-Commit-Position: refs/heads/master@{#355300}