[on-hold][subresource_filter] Add ActivationTracker to track all activated contents

chrome/browser/subresource_filter/subresource_filter_profile_context.h

 // Copyright 2017 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_SUBRESOURCE_FILTER_SUBRESOURCE_FILTER_PROFILE_CONTEXT_H_
 #define CHROME_BROWSER_SUBRESOURCE_FILTER_SUBRESOURCE_FILTER_PROFILE_CONTEXT_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 class Profile;
+class SubresourceFilterActivationTracker;
 class SubresourceFilterContentSettingsManager;
 
 // This class holds profile scoped context for subresource filtering.
 class SubresourceFilterProfileContext : public KeyedService {
  public:
   explicit SubresourceFilterProfileContext(Profile* profile);
   ~SubresourceFilterProfileContext() override;
 
+  SubresourceFilterActivationTracker* activation_tracker() const {
+    return activation_tracker_.get();
+  }
+
  private:
   // KeyedService:
   void Shutdown() override;
 
   std::unique_ptr<SubresourceFilterContentSettingsManager>
       content_settings_manager_;
+  std::unique_ptr<SubresourceFilterActivationTracker> activation_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(SubresourceFilterProfileContext);
 };
 
 #endif  // CHROME_BROWSER_SUBRESOURCE_FILTER_SUBRESOURCE_FILTER_PROFILE_CONTEXT_H_