[iOS] Add a HasActiveStateManager method to BrowserState.

ios/web/browser_state.mm

 // 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.
 
 #include "ios/web/public/browser_state.h"
 
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
 #include "ios/web/active_state_manager_impl.h"
 #import "ios/web/browsing_data_partition_impl.h"
@@ skipping 34 matching lines @@
                                cert_cache_service_handle);
   }
 
   CertificatePolicyCacheHandle* handle =
       static_cast<CertificatePolicyCacheHandle*>(
           browser_state->GetUserData(kCertificatePolicyCacheKeyName));
   return handle->policy_cache;
 }
 
 // static
+bool BrowserState::HasActiveStateManager(BrowserState* browser_state) {
+  DCHECK_CURRENTLY_ON_WEB_THREAD(WebThread::UI);
+  return browser_state->GetUserData(kActiveStateManagerKeyName) != nullptr;
+}
+
+// static
 ActiveStateManager* BrowserState::GetActiveStateManager(
     BrowserState* browser_state) {
   DCHECK_CURRENTLY_ON_WEB_THREAD(WebThread::UI);
   DCHECK(browser_state);
 
   ActiveStateManagerImpl* active_state_manager =
       static_cast<ActiveStateManagerImpl*>(
           browser_state->GetUserData(kActiveStateManagerKeyName));
   if (!active_state_manager) {
     active_state_manager = new ActiveStateManagerImpl(browser_state);
@@ skipping 53 matching lines @@
 // static
 BrowserState* BrowserState::FromSupportsUserData(
     base::SupportsUserData* supports_user_data) {
   if (!supports_user_data ||
       !supports_user_data->GetUserData(kBrowserStateIdentifierKey)) {
     return nullptr;
   }
   return static_cast<BrowserState*>(supports_user_data);
 }
 }  // namespace web