Letting Flash join MediaSession (stack implementaion)

content/browser/media/session/audio_focus_manager.h

Index: content/browser/media/session/audio_focus_manager.h
diff --git a/content/browser/media/session/audio_focus_manager.h b/content/browser/media/session/audio_focus_manager.h
index 6844ae767c402324872af4f787b100f3722e0222..3ccaa7b18234f43aa8c141a972debc40344ccb39 100644
--- a/content/browser/media/session/audio_focus_manager.h
+++ b/content/browser/media/session/audio_focus_manager.h
@@ -5,6 +5,7 @@
 #ifndef CONTENT_BROWSER_MEDIA_SESSION_AUDIO_FOCUS_MANAGER_H_
 #define CONTENT_BROWSER_MEDIA_SESSION_AUDIO_FOCUS_MANAGER_H_
 
+#include <list>
 #include <unordered_map>
 
 #include "base/memory/singleton.h"
@@ -44,6 +45,7 @@ class CONTENT_EXPORT AudioFocusManager {
                     AudioFocusType type);
 
     AudioFocusType type() const;
+    MediaSession* ToMediaSession() const;
 
    private:
     // WebContentsObserver implementation.
@@ -60,35 +62,9 @@ class CONTENT_EXPORT AudioFocusManager {
 
   void OnWebContentsDestroyed(WebContents* web_contents);
 
-  // Internal usage of AbandonAudioFocus using WebContents.
-  void AbandonAudioFocusInternal(WebContents* web_contents);
-
-  // This method is meant to be called when a new session is of type
-  // GainTransientMayDuck. If it is the first one, other clients will be asked
-  // to duck.
-  void MaybeStartDucking() const;
-
-  // This method is meant to be called when a session is no longer of type
-  // GainTransientMayDuck. If it was the last one, other clients will be asked
-  // to no longer duck.
-  void MaybeStopDucking() const;
-
-  // Returns how many sessions require current audio focused session to duck.
-  int TransientMayDuckEntriesCount() const;
-
-  // Internal method to request audio focus of type AudioFocusType::Gain.
-  void RequestAudioFocusGain(WebContents* web_contents);
-
-  // Removes the entry associated with |web_contents| from the
-  // |transient_entries_| if there is one.
-  void MaybeRemoveTransientEntry(WebContents* web_contents);
-
-  // Removes the focused session if it is associated with |web_contents|.
   void MaybeRemoveFocusEntry(WebContents* web_contents);
 
-  std::unordered_map<WebContents*, std::unique_ptr<AudioFocusEntry>>
-      transient_entries_;
-  std::unique_ptr<AudioFocusEntry> focus_entry_;
+  std::list<std::unique_ptr<AudioFocusEntry>> audio_focus_stack_;
 };
 
 }  // namespace content