Revert "[Nav Experiment] Add a wait after restore session."

This reverts commit bcae87b0c7618e2fc61f78a073cf5589fe9679bd.

Reason for revert: This didn't actually fix the problem and
I didn't catch it due to a mistake in testing. The real
problem is that the restore_session request started in 
WKBasedNavigationManager::Restore() was not run, because
|_containerView| is not yet initiated in the new CWVWebView.

Original change's description:
> [Nav Experiment] Add a wait after restore session.
> 
> This fixes WebViewRestorableStateTest when WKBasedNavigationManger is
> enabled. A better approach would be to turn this test into a
> programmatic test so both navigation managers implementations are
> tested, but web::features symbols are not exposed in ios/web_view.
> 
> Bug: 862714
> Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
> Change-Id: I19916a973b566fac32c8995bd199784f0c846a1e
> Reviewed-on: https://chromium-review.googlesource.com/1134046
> Reviewed-by: Eugene But <eugenebut@chromium.org>
> Commit-Queue: Danyao Wang <danyao@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#574367}

TBR=eugenebut@chromium.org,danyao@chromium.org

Change-Id: Ia9d2d127e18264fbf69786c58b71706e0b34ead5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 862714
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Reviewed-on: https://chromium-review.googlesource.com/1135346
Reviewed-by: Danyao Wang <danyao@chromium.org>
Commit-Queue: Danyao Wang <danyao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574577}
1 file changed