Pretend the video has no audio track if it is playing as part of autoplay muted.

third_party/WebKit/public/platform/WebMediaPlayerClient.h

Index: third_party/WebKit/public/platform/WebMediaPlayerClient.h
diff --git a/third_party/WebKit/public/platform/WebMediaPlayerClient.h b/third_party/WebKit/public/platform/WebMediaPlayerClient.h
index d56d5208363a787966c7037c053e509e0c93dd5d..ab76aa13e4d69ed2ffc50c2a7a9dc456d658f5c3 100644
--- a/third_party/WebKit/public/platform/WebMediaPlayerClient.h
+++ b/third_party/WebKit/public/platform/WebMediaPlayerClient.h
@@ -91,6 +91,9 @@ class BLINK_PLATFORM_EXPORT WebMediaPlayerClient {
   virtual void disconnectedFromRemoteDevice() = 0;
   virtual void cancelledRemotePlaybackRequest() = 0;
 
+  // Returns whether the media element is in an autoplay muted state.
+  virtual bool isAutoplayingMuted() = 0;
+
   // Warning: This method will destruct the caller.
   virtual void requestReload(const WebURL& newUrl) = 0;