ObserverList::HasObserver now takes a const pointer.

chrome/browser/search/instant_unittest_base.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 CHROME_BROWSER_SEARCH_INSTANT_UNITTEST_BASE_H_
 #define CHROME_BROWSER_SEARCH_INSTANT_UNITTEST_BASE_H_
 
 #include <string>
 
 #include "base/metrics/field_trial.h"
@@ skipping 24 matching lines @@
   // TLD.
   // It will always use an instant-enabled configuration using a
   // search_terms_replacement_key.
   void SetUserSelectedDefaultSearchProvider(const std::string& base_url);
 
   // Simulates a Google Base URL change as would happen in event of
   // search-domain-check. Note that the GoogleURLTrackerFactory is disabled for
   // tests, so this is required.
   void NotifyGoogleBaseURLUpdate(const std::string& new_google_base_url);
 
-  bool IsInstantServiceObserver(InstantServiceObserver* observer);
+  bool IsInstantServiceObserver(const InstantServiceObserver* observer) const;
 
   InstantService* instant_service_;
   TemplateURLService* template_url_service_;
   scoped_ptr<base::FieldTrialList> field_trial_list_;
 
  private:
   // BrowserWithTestWindowTest override:
   TestingProfile* CreateProfile() override;
 
   void SetUpHelper();
 };
 
 #endif  // CHROME_BROWSER_SEARCH_INSTANT_UNITTEST_BASE_H_