Let Flash join and be controlled by media session

media/base/media_switches.cc

Index: media/base/media_switches.cc
diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
index 846f25e75aa6ee2cabc06eebe3636a30b4736238..83a2276c6a92ac456c371dcce32e7efb41ee382b 100644
--- a/media/base/media_switches.cc
+++ b/media/base/media_switches.cc
@@ -127,6 +127,13 @@ const char kEnableVp9InMp4[] = "enable-vp9-in-mp4";
 
 namespace media {
 
+#if defined(ENABLE_PLUGINS)
+// Let flash join and be controlled by media session, only valid when
+// |kEnableDefaultMediaSession| is on.
+const base::Feature kFlashJoinsMediaSession{"flash-join-media-session",
+                                            base::FEATURE_DISABLED_BY_DEFAULT};
+#endif  // defined(ENABLE_PLUGINS)
+
 // Use new audio rendering mixer.
 const base::Feature kNewAudioRenderingMixingStrategy{
     "NewAudioRenderingMixingStrategy", base::FEATURE_DISABLED_BY_DEFAULT};