Deleted -[Tab webViewRemoved] method.

This method is not called and is probaly a cruft from CRWWebDelegate.

Bug: 681867
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ib6dd682c5889b540008b6807ffdc0bbd07ac83e4
Reviewed-on: https://chromium-review.googlesource.com/811291
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522387}

ios/chrome/browser/tabs/tab.mm

@@ -984,10 +984,6 @@ void TabInfoBarObserver::OnInfoBarReplaced(infobars::InfoBar* old_infobar,
   return [snapshotOverlayProvider_ snapshotOverlaysForTab:self];
 }
 
-- (void)webViewRemoved {
-  [_openInController disable];
-}
-
 - (BOOL)webController:(CRWWebController*)webController
         shouldOpenURL:(const GURL&)url
       mainDocumentURL:(const GURL&)mainDocumentURL {