Add about_flag for experimenting MediaSession on Desktop

media/base/media_switches.cc

 // 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.
 
 #include "build/build_config.h"
 #include "media/base/media_switches.h"
 
 namespace switches {
 
 // Allow users to specify a custom buffer size for debugging purpose.
@@ skipping 48 matching lines @@
 
 // Number of buffers to use for WaveOut.
 const char kWaveOutBuffers[] = "waveout-buffers";
 #endif
 
 #if defined(USE_CRAS)
 // Use CRAS, the ChromeOS audio server.
 const char kUseCras[] = "use-cras";
 #endif
 
-#if !defined(OS_ANDROID)
+#if !defined(OS_ANDROID) || defined(ENABLE_PLUGINS)
 // Use a media session for each tabs in a way that two tabs can't play on top of
 // each other. This is different from the Media Session API as it is enabling a
-// default behaviour for the browser.
+// default behaviour for the browser. The allowed values are: "" (empty),
+// |kEnableDefaultMediaSessionWithFlash|.
 const char kEnableDefaultMediaSession[] = "enable-default-media-session";
-#endif
+#endif  // !defined(OS_ANDROID) || defined(ENABLE_PLUGINS)
+
+#if defined(ENABLE_PLUGINS)
+// This value is used as an option for |kEnableDefaultMediaSession|.
+const char kEnableDefaultMediaSessionWithFlash[] = "with-flash";
+#endif  // defined(ENABLE_PLUGINS)
 
 // Use fake device for Media Stream to replace actual camera and microphone.
 const char kUseFakeDeviceForMediaStream[] = "use-fake-device-for-media-stream";
 
 // Use an .y4m file to play as the webcam. See the comments in
 // media/capture/video/file_video_capture_device.h for more details.
 const char kUseFileForFakeVideoCapture[] = "use-file-for-fake-video-capture";
 
 // Play a .wav file as the microphone. Note that for WebRTC calls we'll treat
 // the bits as if they came from the microphone, which means you should disable
@@ skipping 36 matching lines @@
 }  // namespace switches
 
 namespace media {
 
 #if defined(OS_WIN)
 // Enables H264 HW encode acceleration using Media Foundation for Windows.
 const base::Feature kMediaFoundationH264Encoding{
     "MediaFoundationH264Encoding", base::FEATURE_DISABLED_BY_DEFAULT};
 #endif  // defined(OS_WIN)
 
-#if defined(ENABLE_PLUGINS)
-// Let flash join and be controlled by media session, only valid when
-// |kEnableDefaultMediaSession| is on.
-const base::Feature kFlashJoinsMediaSession{"FlashJoinsMediaSession",
-                                            base::FEATURE_DISABLED_BY_DEFAULT};
-#endif  // defined(ENABLE_PLUGINS)
-
 // Use new audio rendering mixer.
 const base::Feature kNewAudioRenderingMixingStrategy{
     "NewAudioRenderingMixingStrategy", base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Only used for disabling overlay fullscreen (aka SurfaceView) in Clank.
 const base::Feature kOverlayFullscreenVideo{"overlay-fullscreen-video",
                                             base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Let videos be resumed via remote controls (for example, the notification)
 // when in background.
@@ skipping 20 matching lines @@
 const base::Feature kExternalClearKeyForTesting{
     "external-clear-key-for-testing", base::FEATURE_DISABLED_BY_DEFAULT};
 
 #if defined(OS_ANDROID)
 // Replaces WPMA by the MediaPlayerRenderer for HLS and fallback playback.
 const base::Feature kAndroidMediaPlayerRenderer{
     "android-media-player-renderer", base::FEATURE_DISABLED_BY_DEFAULT};
 #endif
 
 }  // namespace media