Added stub MediaSourcePlayer for developing behind the flag

content/browser/media/android/browser_media_player_manager.cc

Index: content/browser/media/android/browser_media_player_manager.cc
diff --git a/content/browser/media/android/browser_media_player_manager.cc b/content/browser/media/android/browser_media_player_manager.cc
index 20fd34e89de28e72e243f44ec986366dcabc57af..a241bb08789303762c65160cfdb3b8357f67bc8a 100644
--- a/content/browser/media/android/browser_media_player_manager.cc
+++ b/content/browser/media/android/browser_media_player_manager.cc
@@ -25,11 +25,13 @@
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
+#include "media/base/android/legacy_media_source_player.h"
 #include "media/base/android/media_player_bridge.h"
 #include "media/base/android/media_source_player.h"
 #include "media/base/android/media_url_interceptor.h"
 #include "media/base/media_switches.h"
 
+using media::LegacyMediaSourcePlayer;
 using media::MediaPlayerAndroid;
 using media::MediaPlayerBridge;
 using media::MediaPlayerManager;
@@ -113,13 +115,23 @@ MediaPlayerAndroid* BrowserMediaPlayerManager::CreateMediaPlayer(
     }
 
     case MEDIA_PLAYER_TYPE_MEDIA_SOURCE: {
-      return new MediaSourcePlayer(
-          media_player_params.player_id,
-          manager,
-          base::Bind(&BrowserMediaPlayerManager::OnMediaResourcesRequested,
-                     weak_ptr_factory_.GetWeakPtr()),
-          demuxer->CreateDemuxer(media_player_params.demuxer_client_id),
-          media_player_params.frame_url);
+      if (base::CommandLine::ForCurrentProcess()->
+          HasSwitch(switches::kEnableMediaThreadForMediaPlayback))
+        return new MediaSourcePlayer(
+            media_player_params.player_id,
+            manager,
+            base::Bind(&BrowserMediaPlayerManager::OnMediaResourcesRequested,
+                       weak_ptr_factory_.GetWeakPtr()),
+            demuxer->CreateDemuxer(media_player_params.demuxer_client_id),
+            media_player_params.frame_url);
+      else
+        return new LegacyMediaSourcePlayer(
+            media_player_params.player_id,
+            manager,
+            base::Bind(&BrowserMediaPlayerManager::OnMediaResourcesRequested,
+                       weak_ptr_factory_.GetWeakPtr()),
+            demuxer->CreateDemuxer(media_player_params.demuxer_client_id),
+            media_player_params.frame_url);
     }
   }