[Media] Plumb a feature parameter for the background video keyframe distance.

media/blink/webmediaplayer_impl.h

 // Copyright 2013 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 MEDIA_BLINK_WEBMEDIAPLAYER_IMPL_H_
 #define MEDIA_BLINK_WEBMEDIAPLAYER_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 632 matching lines @@
   bool preroll_attempt_pending_;
   base::TimeTicks preroll_attempt_start_time_;
 
   std::unique_ptr<base::TickClock> tick_clock_;
 
   // Monitors the player events.
   base::WeakPtr<MediaObserver> observer_;
 
   // The maximum video keyframe distance that allows triggering background
   // playback optimizations.
-  // 10 seconds by default but can be overridden by a Finch experiment.
-  base::TimeDelta max_keyframe_distance_to_disable_background_video_ =
-      base::TimeDelta::FromSeconds(10);
+  base::TimeDelta max_keyframe_distance_to_disable_background_video_;
 
   // Whether disabled the video track as an optimization.
   bool video_track_disabled_ = false;
 
   // Whether the pipeline is being resumed at the moment.
   bool is_pipeline_resuming_ = false;
 
   // Pipeline statistics overridden by tests.
   base::Optional<PipelineStatistics> pipeline_statistics_for_test_;
 
   // Pipeline media duration overridden by tests.
   base::Optional<base::TimeDelta> pipeline_media_duration_for_test_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_WEBMEDIAPLAYER_IMPL_H_