Use the previews black list for offline previews

components/previews/core/previews_io_data.h

 // Copyright 2016 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_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_
 #define COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
+#include "components/previews/core/previews_decider.h"
 #include "components/previews/core/previews_opt_out_store.h"
 
 class GURL;
 
+namespace net {
+class URLRequest;
+}
+
 namespace previews {
 class PreviewsBlackList;
 class PreviewsUIService;
 
 // A class to manage the IO portion of inter-thread communication between
 // previews/ objects. Created on the UI thread, but used only on the IO thread
 // after initialization.
-class PreviewsIOData {
+class PreviewsIOData : public PreviewsDecider {
  public:
   PreviewsIOData(
       const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner,
       const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
-  virtual ~PreviewsIOData();
+  ~PreviewsIOData() override;
 
   // Stores |previews_ui_service| as |previews_ui_service_| and posts a task to
   // InitializeOnIOThread on the IO thread.
   void Initialize(base::WeakPtr<PreviewsUIService> previews_ui_service,
                   std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store);
 
   // Adds a navigation to |url| to the black list with result |opt_out|.
   void AddPreviewNavigation(const GURL& url, bool opt_out, PreviewsType type);
 
   // Clears the history of the black list between |begin_time| and |end_time|,
   // both inclusive.
   void ClearBlackList(base::Time begin_time, base::Time end_time);
 
   // The previews black list that decides whether a navigation can use previews.
   PreviewsBlackList* black_list() const { return previews_black_list_.get(); }
 
+  // Get a weak pointer to the PreviewsDecider base class.
+  base::WeakPtr<PreviewsDecider> PreviewsDeciderWeakPtr() {
+    return weak_factory_.GetWeakPtr();
+  }
+
+  // PreviewsDecider implementation:
+  bool ShouldAllowPreview(net::URLRequest* request, PreviewsType type) override;

[jianli, 2016/10/05 01:13:02]

Since you're not going to change request object, probably adding "const" to its
type is better.

[RyanSturm, 2016/10/05 03:09:40]

Done.

+
  protected:
   // Posts a task to SetIOData for |previews_ui_service_| on the UI thread with
   // a weak pointer to |this|. Virtualized for testing.
   virtual void InitializeOnIOThread(
       std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store);
 
  private:
   // The UI thread portion of the inter-thread communication for previews.
   base::WeakPtr<PreviewsUIService> previews_ui_service_;
 
   std::unique_ptr<PreviewsBlackList> previews_black_list_;
 
   // The UI and IO thread task runners. |ui_task_runner_| is used to post
   // tasks to |previews_ui_service_|, and |io_task_runner_| is used to post from
   // Initialize to InitializeOnIOThread as well as verify that execution is
   // happening on the IO thread.
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
 
   base::WeakPtrFactory<PreviewsIOData> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PreviewsIOData);
 };
 
 }  // namespace previews
 
 #endif  // COMPONENTS_PREVIEWS_CORE_PREVIEWS_IO_DATA_H_