[iOS] Add a HasActiveStateManager method to BrowserState.

ios/web/public/browser_state.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef IOS_WEB_PUBLIC_BROWSER_STATE_H_
 #define IOS_WEB_PUBLIC_BROWSER_STATE_H_
 
 #include "base/supports_user_data.h"
 
 namespace base {
@@ skipping 16 matching lines @@
 // It lives on the UI thread. All these methods must only be called on the UI
 // thread.
 class BrowserState : public base::SupportsUserData {
  public:
   ~BrowserState() override;
 
   // static
   static scoped_refptr<CertificatePolicyCache> GetCertificatePolicyCache(
       BrowserState* browser_state);
 
+  // Returns whether |browser_state_| has an associated ActiveStateManager.
+  // Must only be accessed from main thread.
+  static bool HasActiveStateManager(BrowserState* browser_state);
+
   // Returns the ActiveStateManager associated with |browser_state.|
   // Lazily creates one if an ActiveStateManager is not already associated with
   // the |browser_state|. |browser_state| cannot be a nullptr.  Must be accessed
   // only from the main thread.
   static ActiveStateManager* GetActiveStateManager(BrowserState* browser_state);
 
   // Returns the BrowsingDataPartition associated with this browser_state.
   // Lazily creates one if a BrowsingDataPartition is not already associated
   // with the |browser_state|. |browser_state| cannot be a nullptr.  Must be
   // accessed only from the main thread.
@@ skipping 32 matching lines @@
 
   // The URLDataManagerIOSBackend instance associated with this BrowserState.
   // Created and destroyed on the IO thread, and should be accessed only from
   // the IO thread.
   URLDataManagerIOSBackend* url_data_manager_ios_backend_;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_BROWSER_STATE_H_