media-internals: Store updates when cannot update.

content/browser/media/media_internals.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_
 #define CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_
 
+#include <list>
+#include <map>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "base/strings/string16.h"
 #include "base/synchronization/lock.h"
 #include "base/values.h"
 #include "content/common/content_export.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 #include "media/audio/audio_logging.h"
 #include "media/base/media_log.h"
 #include "media/video/capture/video_capture_device_info.h"
 
 namespace media {
 class AudioParameters;
 struct MediaLogEvent;
 }
 
 namespace content {
 
 // This class stores information about currently active media.
 class CONTENT_EXPORT MediaInternals
-    : NON_EXPORTED_BASE(public media::AudioLogFactory) {
+    : NON_EXPORTED_BASE(public media::AudioLogFactory),
+      public NotificationObserver {
  public:
   // Called with the update string.
   typedef base::Callback<void(const base::string16&)> UpdateCallback;
 
   static MediaInternals* GetInstance();
 
   ~MediaInternals() override;
 
+  // NotificationObserver implementation.
+  void Observe(int type,
+               const NotificationSource& source,
+               const NotificationDetails& details) override;
+
   // Called when a MediaEvent occurs.
   void OnMediaEvents(int render_process_id,
                      const std::vector<media::MediaLogEvent>& events);
 
   // Add/remove update callbacks (see above). Must be called on the UI thread.
   // The callbacks must also be fired on UI thread.
   void AddUpdateCallback(const UpdateCallback& callback);
   void RemoveUpdateCallback(const UpdateCallback& callback);
 
   // Whether there are any update callbacks available. Can be called on any
   // thread.
   bool CanUpdate();
 
+  // Replay all saved media events.
+  void SendHistoricalMediaEvents();
+
   // Sends all audio cached data to each registered UpdateCallback.
   void SendAudioStreamData();
 
   // Sends all video capture capabilities cached data to each registered
   // UpdateCallback.
   void SendVideoCaptureDeviceCapabilities();
 
   // Called to inform of the capabilities enumerated for video devices.
   void UpdateVideoCaptureDeviceCapabilities(
       const media::VideoCaptureDeviceInfos& video_capture_device_infos);
@@ skipping 10 matching lines @@
                                            media::AudioLog* audio_log);
 
  private:
   // Inner class to handle reporting pipelinestatus to UMA
   class MediaInternalsUMAHandler;
 
   friend class AudioLogImpl;
   friend class MediaInternalsTest;
   friend struct base::DefaultLazyInstanceTraits<MediaInternals>;
 
+  // Pending events for a particular process.
+  using PendingEvents = std::list<media::MediaLogEvent>;
+
+  // The maps between process ID and PendingEvents.
+  using PendingEventsMap = std::map<int, PendingEvents>;
+
   MediaInternals();
 
   // Sends |update| to each registered UpdateCallback.  Safe to call from any
   // thread, but will forward to the IO thread.
   void SendUpdate(const base::string16& update);
 
+  // Saves |event| so that it can be sent later in SendHistoricalMediaEvents().
+  void SaveEvent(int process_id, const media::MediaLogEvent& event);
+
   // Caches |value| under |cache_key| so that future SendAudioLogUpdate() calls
   // will include the current data.  Calls JavaScript |function|(|value|) for
   // each registered UpdateCallback.
   enum AudioLogUpdateType {
     CREATE,             // Creates a new AudioLog cache entry.
     UPDATE_IF_EXISTS,   // Updates an existing AudioLog cache entry, does
                         // nothing if it doesn't exist.
     UPDATE_AND_DELETE,  // Deletes an existing AudioLog cache entry.
   };
   void SendAudioLogUpdate(AudioLogUpdateType type,
                           const std::string& cache_key,
                           const std::string& function,
                           const base::DictionaryValue* value);
 
   // Must only be accessed on the UI thread.
   std::vector<UpdateCallback> update_callbacks_;
 
   // Must only be accessed on the IO thread.
   base::ListValue video_capture_capabilities_cached_data_;
 
+  NotificationRegistrar registrar_;
+
   // All variables below must be accessed under |lock_|.
   base::Lock lock_;
   bool can_update_;
+  PendingEventsMap pending_events_map_;
   base::DictionaryValue audio_streams_cached_data_;
   int owner_ids_[AUDIO_COMPONENT_MAX];
   scoped_ptr<MediaInternalsUMAHandler> uma_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaInternals);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_