Create autoplay policy flag and merge cross-origin autoplay blocking into it.

media/base/media_switches.h

Index: media/base/media_switches.h
diff --git a/media/base/media_switches.h b/media/base/media_switches.h
index b2234d1a2a9ff861c265f6e3f643da3aff6c0e1a..0b688d7b5aff22a3d30ab11231505938e0347d7b 100644
--- a/media/base/media_switches.h
+++ b/media/base/media_switches.h
@@ -17,6 +17,8 @@ namespace switches {
 
 MEDIA_EXPORT extern const char kAudioBufferSize[];
 
+MEDIA_EXPORT extern const char kAutoplayPolicy[];
+
 MEDIA_EXPORT extern const char kVideoThreads[];
 
 MEDIA_EXPORT extern const char kEnableMediaSuspend[];
@@ -75,6 +77,14 @@ MEDIA_EXPORT extern const char kForceVideoOverlays[];
 MEDIA_EXPORT extern const char kMSEAudioBufferSizeLimit[];
 MEDIA_EXPORT extern const char kMSEVideoBufferSizeLimit[];
 
+namespace autoplay {
+
+MEDIA_EXPORT extern const char kCrossOriginUserGestureRequiredPolicy[];
+MEDIA_EXPORT extern const char kUserGestureRequiredPolicy[];
+MEDIA_EXPORT extern const char kNoRestrictionsPolicy[];
+
+}  // namespace autoplay
+
 }  // namespace switches
 
 namespace media {
@@ -82,11 +92,7 @@ namespace media {
 // All features in alphabetical order. The features should be documented
 // alongside the definition of their values in the .cc file.
 
-#if defined(OS_WIN)
-MEDIA_EXPORT extern const base::Feature kD3D11VideoDecoding;
-MEDIA_EXPORT extern const base::Feature kMediaFoundationH264Encoding;
-#endif  // defined(OS_WIN)
-
+MEDIA_EXPORT extern const base::Feature kAutoplayPolicy;
 MEDIA_EXPORT extern const base::Feature kNewAudioRenderingMixingStrategy;
 MEDIA_EXPORT extern const base::Feature kOverlayFullscreenVideo;
 MEDIA_EXPORT extern const base::Feature kResumeBackgroundVideo;
@@ -103,6 +109,12 @@ MEDIA_EXPORT extern const base::Feature kAndroidMediaPlayerRenderer;
 MEDIA_EXPORT extern const base::Feature kVideoFullscreenOrientationLock;
 MEDIA_EXPORT extern const base::Feature kMediaDrmPersistentLicense;
 #endif  // defined(OS_ANDROID)
+
+#if defined(OS_WIN)
+MEDIA_EXPORT extern const base::Feature kD3D11VideoDecoding;
+MEDIA_EXPORT extern const base::Feature kMediaFoundationH264Encoding;
+#endif  // defined(OS_WIN)
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_SWITCHES_H_