[Media] Add a finch trial param for background MediaSource videos

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 3d0566c37d5de42f838c0fc3ca1912ad29472a0d..94ae46cb6f6e8fb0238a35fb9512cc2ade374c95 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -2880,6 +2880,11 @@ blink::WebMediaPlayer* RenderFrameImpl::CreateMediaPlayer(
       base::TimeDelta::FromMilliseconds(base::GetFieldTrialParamByFeatureAsInt(
           media::kBackgroundVideoTrackOptimization, "max_keyframe_distance_ms",
           base::TimeDelta::FromSeconds(10).InMilliseconds()));
+  base::TimeDelta max_keyframe_distance_to_disable_background_video_mse =
+      base::TimeDelta::FromMilliseconds(base::GetFieldTrialParamByFeatureAsInt(
+          media::kBackgroundVideoTrackOptimization,
+          "max_keyframe_distance_media_source_ms",
+          base::TimeDelta::FromSeconds(10).InMilliseconds()));
 
   media::WebMediaPlayerParams params(
       base::Bind(&ContentRendererClient::DeferMediaLoad,
@@ -2894,6 +2899,7 @@ blink::WebMediaPlayer* RenderFrameImpl::CreateMediaPlayer(
                  base::Unretained(blink::MainThreadIsolate())),
       initial_cdm, media_surface_manager_, media_observer,
       max_keyframe_distance_to_disable_background_video,
+      max_keyframe_distance_to_disable_background_video_mse,
       GetWebkitPreferences().enable_instant_source_buffer_gc,
       GetContentClient()->renderer()->AllowMediaSuspend(),
       embedded_media_experience_enabled);