Add --enable-internal-media-session to trigger the MediaSession backend.

media/base/media_switches.h

 // Copyright (c) 2012 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.
 
 // Defines all the "media" command-line switches.
 
 #ifndef MEDIA_BASE_MEDIA_SWITCHES_H_
 #define MEDIA_BASE_MEDIA_SWITCHES_H_
 
 #include "base/feature_list.h"
@@ skipping 68 matching lines @@
 
 MEDIA_EXPORT extern const char kEnableVp9InMp4[];
 
 MEDIA_EXPORT extern const char kForceVideoOverlays[];
 
 MEDIA_EXPORT extern const char kMSEAudioBufferSizeLimit[];
 MEDIA_EXPORT extern const char kMSEVideoBufferSizeLimit[];
 
 MEDIA_EXPORT extern const char kIgnoreAutoplayRestrictionsForTests[];
 
+#if !defined(OS_ANDROID)
+MEDIA_EXPORT extern const char kEnableInternalMediaSession[];
+#endif  // !defined(OS_ANDROID)
+
 namespace autoplay {
 
 MEDIA_EXPORT extern const char kNoUserGestureRequiredPolicy[];
 MEDIA_EXPORT extern const char kUserGestureRequiredPolicy[];
 MEDIA_EXPORT extern const char kUserGestureRequiredForCrossOriginPolicy[];
 
 }  // namespace autoplay
 
 }  // namespace switches
 
@@ skipping 33 matching lines @@
 // autoplay policy. In other words, it will take into account the default policy
 // if none is specified via the command line and options passed for testing.
 // Returns one of the possible autoplay policy switches from the
 // switches::autoplay namespace.
 MEDIA_EXPORT std::string GetEffectiveAutoplayPolicy(
     const base::CommandLine& command_line);
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_SWITCHES_H_