Suspend idle WebMediaPlayer instances after some time.

content/renderer/media/renderer_webmediaplayer_delegate.h

 // Copyright 2015 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_RENDERER_MEDIA_RENDERER_WEBMEDIAPLAYER_DELEGATE_H_
 #define CONTENT_RENDERER_MEDIA_RENDERER_WEBMEDIAPLAYER_DELEGATE_H_
 
+#include <map>
+
 #include "base/id_map.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/default_tick_clock.h"
+#include "base/timer/timer.h"
+#include "content/common/content_export.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "media/blink/webmediaplayer_delegate.h"
 
 namespace blink {
 class WebMediaPlayer;
 }
 
 namespace media {
 
 // An interface to allow a WebMediaPlayerImpl to communicate changes of state
 // to objects that need to know.
-class RendererWebMediaPlayerDelegate
+class CONTENT_EXPORT RendererWebMediaPlayerDelegate
     : public content::RenderFrameObserver,
-      public WebMediaPlayerDelegate,
-      public base::SupportsWeakPtr<RendererWebMediaPlayerDelegate> {
+      public NON_EXPORTED_BASE(WebMediaPlayerDelegate),
+      public NON_EXPORTED_BASE(
+          base::SupportsWeakPtr<RendererWebMediaPlayerDelegate>) {
  public:
   explicit RendererWebMediaPlayerDelegate(content::RenderFrame* render_frame);
   ~RendererWebMediaPlayerDelegate() override;
 
   // Returns true if this RenderFrame has ever seen media playback before.
   bool has_played_media() const { return has_played_media_; }
 
   // WebMediaPlayerDelegate implementation.
   int AddObserver(Observer* observer) override;
   void RemoveObserver(int delegate_id) override;
   void DidPlay(int delegate_id,
                bool has_video,
                bool has_audio,
                bool is_remote,
                base::TimeDelta duration) override;
   void DidPause(int delegate_id, bool reached_end_of_stream) override;
   void PlayerGone(int delegate_id) override;
   bool IsHidden() override;
 
   // content::RenderFrameObserver overrides.
   void WasHidden() override;
   void WasShown() override;
   bool OnMessageReceived(const IPC::Message& msg) override;
 
+  // Sets |idle_cleanup_enabled_| to true, zeros out |idle_cleanup_interval_|,
+  // and sets |idle_timeout_| to |idle_timeout|. A zero cleanup interval will
+  // cause the idle timer to run with each run of the message loop.
+  void EnableInstantIdleCleanupForTesting(base::TimeDelta idle_timeout,
+                                          base::TickClock* tick_clock);
+  bool IsIdleCleanupTimerRunningForTesting() const {
+    return idle_cleanup_timer_.IsRunning();
+  }
+
  private:
   void OnMediaDelegatePause(int delegate_id);
   void OnMediaDelegatePlay(int delegate_id);
   void OnMediaDelegateSuspendAllMediaPlayers();
   void OnMediaDelegateVolumeMultiplierUpdate(int delegate_id,
                                              double multiplier);
 
+  // Adds or removes a delegate from |idle_delegate_map_|. The first insertion
+  // or last removal will start or stop |idle_cleanup_timer_| respectively.
+  void AddIdleDelegate(int delegate_id);
+  void RemoveIdleDelegate(int delegate_id);
+
+  // Runs periodically to suspend idle delegates in |idle_delegate_map_|.
+  void CleanupIdleDelegates();
+
   bool has_played_media_ = false;
   IDMap<Observer> id_map_;
 
+  // Tracks which delegates have entered an idle state. After some period of
+  // inactivity these players will be suspended to release unused resources.
+  bool idle_cleanup_running_ = false;
+  std::map<int, base::TimeTicks> idle_delegate_map_;
+  base::RepeatingTimer idle_cleanup_timer_;
+
+  // Controls whether cleanup of idle delegates is enabled or not as well as the
+  // polling interval and timeout period for delegates; overridden for testing.
+  bool idle_cleanup_enabled_ = false;
+
+  // Amount of time allowed to elapse after a delegate enters the paused before
+  // the delegate is suspended.
+  base::TimeDelta idle_timeout_;
+
+  // The polling interval used for checking the delegates to see if any have
+  // exceeded |idle_timeout_| since their last pause state.
+  base::TimeDelta idle_cleanup_interval_;
+
+  // Clock used for calculating when delegates have expired. May be overridden
+  // for testing.
+  scoped_ptr<base::DefaultTickClock> default_tick_clock_;
+  base::TickClock* tick_clock_;
+
   DISALLOW_COPY_AND_ASSIGN(RendererWebMediaPlayerDelegate);
 };
 
 }  // namespace media
 
 #endif  // CONTENT_RENDERER_MEDIA_RENDERER_WEBMEDIAPLAYER_DELEGATE_H_