Introduce AsyncDocumentSubresourceFilter.

components/subresource_filter/content/browser/verified_ruleset_dealer.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 COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_VERIFIED_RULESET_DEALER_H_
 #define COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_VERIFIED_RULESET_DEALER_H_
 
 #include <memory>
 
 #include "base/callback_forward.h"
@@ skipping 123 matching lines @@
   // Returns the |task_runner| on which the VerifiedRuleset, as well as the
   // MemoryMappedRuleset it holds a reference to, should be accessed.
   base::SequencedTaskRunner* task_runner() { return task_runner_; }
 
   // Invokes |callback| on |task_runner|, providing a pointer to the underlying
   // VerifiedRuleset as an argument. The pointer is guaranteed to be valid at
   // least until the callback returns.
   void GetRulesetAsync(base::Callback<void(VerifiedRuleset*)> callback);
 
  private:
+  // This is to allow ADSF to post |ruleset_.get()| pointer to |task_runner_|.
+  friend class AsyncDocumentSubresourceFilter;
+
   // Note: Raw pointer, |ruleset_| already holds a reference to |task_runner_|.
   base::SequencedTaskRunner* task_runner_;
   std::unique_ptr<VerifiedRuleset, base::OnTaskRunnerDeleter> ruleset_;
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(Handle);
 };
 
 }  // namespace subresource_filter
 
 #endif  // COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_VERIFIED_RULESET_DEALER_H_