chromium/content/public/renderer/render_frame_observer_tracker.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Helper class used to find the RenderFrameObservers for a given RenderFrame.
//
// Example usage:
//
//   class MyRFO : public RenderFrameObserver,
//                 public RenderFrameObserverTracker<MyRFO> {
//     ...
//   };
//
//   MyRFO::MyRFO(RenderFrame* render_frame)
//       : RenderFrameObserver(render_frame),
//         RenderFrameObserverTracker<MyRFO>(render_frame) {
//     ...
//   }
//
//  void SomeFunction(RenderFrame* rf) {
//    MyRFO* my_rfo = new MyRFO(rf);
//    MyRFO* my_rfo_tracked = MyRFO::Get(rf);
//    // my_rfo == my_rfo_tracked
//  }

#ifndef CONTENT_PUBLIC_RENDERER_RENDER_FRAME_OBSERVER_TRACKER_H_
#define CONTENT_PUBLIC_RENDERER_RENDER_FRAME_OBSERVER_TRACKER_H_

#include <map>

#include "base/lazy_instance.h"
#include "base/memory/raw_ptr.h"

namespace content {

class RenderFrame;

template <class T>
class RenderFrameObserverTracker { … };

template <class T>
typename base::LazyInstance<
    std::map<const RenderFrame*, RenderFrameObserverTracker<T>*>>::
    DestructorAtExit RenderFrameObserverTracker<T>::render_frame_map_ = …;

}  // namespace content

#endif  // CONTENT_PUBLIC_RENDERER_RENDER_FRAME_OBSERVER_TRACKER_H_