Componentize //chrome/browser/prefs/tracked.

chrome/browser/prefs/tracked/interceptable_pref_filter.h

-// Copyright 2014 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_PREFS_TRACKED_INTERCEPTABLE_PREF_FILTER_H_
-#define CHROME_BROWSER_PREFS_TRACKED_INTERCEPTABLE_PREF_FILTER_H_
-
-#include "base/callback.h"
-#include "base/memory/weak_ptr.h"
-#include "base/prefs/pref_filter.h"
-#include "base/values.h"
-
-// A partial implementation of a PrefFilter whose FilterOnLoad call may be
-// intercepted by a FilterOnLoadInterceptor. Implementations of
-// InterceptablePrefFilter are expected to override FinalizeFilterOnLoad rather
-// than re-overriding FilterOnLoad.
-class InterceptablePrefFilter
-    : public PrefFilter,
-      public base::SupportsWeakPtr<InterceptablePrefFilter> {
- public:
-  // A callback to be invoked by a FilterOnLoadInterceptor when its ready to
-  // hand back the |prefs| it was handed for early filtering. |prefs_altered|
-  // indicates whether the |prefs| were actually altered by the
-  // FilterOnLoadInterceptor before being handed back.
-  typedef base::Callback<void(scoped_ptr<base::DictionaryValue> prefs,
-                              bool prefs_altered)> FinalizeFilterOnLoadCallback;
-
-  // A callback to be invoked from FilterOnLoad. It takes ownership of prefs
-  // and may modify them before handing them back to this
-  // InterceptablePrefFilter via |finalize_filter_on_load|.
-  typedef base::Callback<
-      void(const FinalizeFilterOnLoadCallback& finalize_filter_on_load,
-           scoped_ptr<base::DictionaryValue> prefs)> FilterOnLoadInterceptor;
-
-  InterceptablePrefFilter();
-  ~InterceptablePrefFilter() override;
-
-  // PrefFilter partial implementation.
-  void FilterOnLoad(
-      const PostFilterOnLoadCallback& post_filter_on_load_callback,
-      scoped_ptr<base::DictionaryValue> pref_store_contents) override;
-
-  // Registers |filter_on_load_interceptor| to intercept the next FilterOnLoad
-  // event. At most one FilterOnLoadInterceptor should be registered per
-  // PrefFilter.
-  void InterceptNextFilterOnLoad(
-      const FilterOnLoadInterceptor& filter_on_load_interceptor);
-
- private:
-  // Does any extra filtering required by the implementation of this
-  // InterceptablePrefFilter and hands back the |pref_store_contents| to the
-  // initial caller of FilterOnLoad.
-  virtual void FinalizeFilterOnLoad(
-      const PostFilterOnLoadCallback& post_filter_on_load_callback,
-      scoped_ptr<base::DictionaryValue> pref_store_contents,
-      bool prefs_altered) = 0;
-
-  // Callback to be invoked only once (and subsequently reset) on the next
-  // FilterOnLoad event. It will be allowed to modify the |prefs| handed to
-  // FilterOnLoad before handing them back to this PrefHashFilter.
-  FilterOnLoadInterceptor filter_on_load_interceptor_;
-};
-
-#endif  // CHROME_BROWSER_PREFS_TRACKED_INTERCEPTABLE_PREF_FILTER_H_