[ios] WebStateList owns all WebState it manages.

ios/chrome/browser/ui/contextual_search/contextual_search_controller.h

Index: ios/chrome/browser/ui/contextual_search/contextual_search_controller.h
diff --git a/ios/chrome/browser/ui/contextual_search/contextual_search_controller.h b/ios/chrome/browser/ui/contextual_search/contextual_search_controller.h
index f7a97dacc445bb50ab731ec946303d225433f193..2294b35bd3b5b239f57ca59e01ebec850c4a59b1 100644
--- a/ios/chrome/browser/ui/contextual_search/contextual_search_controller.h
+++ b/ios/chrome/browser/ui/contextual_search/contextual_search_controller.h
@@ -22,6 +22,7 @@ class WebState;
 class GURL;
 @class Tab;
 @class TouchToSearchPermissionsMediator;
+struct WebStateOpener;
 
 namespace ContextualSearch {
 // Possible reason for panel state changes.
@@ -50,8 +51,10 @@ enum StateChangeReason {
 @class ContextualSearchResultsView;
 
 @protocol ContextualSearchTabProvider<NSObject>
-// Disassociate the internal Tab object from this view and return it.
-- (Tab*)releaseTab;
+// Disassociate the internal WebState from this view and return it.
+- (std::unique_ptr<web::WebState>)releaseWebState;
+// Information about the opener of the internal WebState.
+- (WebStateOpener)webStateOpener;
 @end
 
 @protocol ContextualSearchControllerDelegate<NSObject>