Make tab audible and muted states and cause available for an extension API

content/browser/media/audio_stream_monitor.cc

Index: content/browser/media/audio_stream_monitor.cc
diff --git a/content/browser/media/audio_stream_monitor.cc b/content/browser/media/audio_stream_monitor.cc
index 1d2f76f7f2c02f986f5b52122834363ff96be1e8..336063069eda096fca779ca61d4069866c8e2167 100644
--- a/content/browser/media/audio_stream_monitor.cc
+++ b/content/browser/media/audio_stream_monitor.cc
@@ -26,11 +26,11 @@ AudioStreamMonitor* AudioStreamMonitorFromRenderFrame(int render_process_id,
 
 }  // namespace
 
-AudioStreamMonitor::AudioStreamMonitor(WebContents* contents)
-    : web_contents_(contents),
+AudioStreamMonitor::AudioStreamMonitor(const AudibleChangeCallback& callback)
+    : audible_change_callback_(callback),
       clock_(&default_tick_clock_),
       was_recently_audible_(false) {
-  DCHECK(web_contents_);
+  DCHECK(!audible_change_callback_.is_null());
 }
 
 AudioStreamMonitor::~AudioStreamMonitor() {}
@@ -146,7 +146,7 @@ void AudioStreamMonitor::MaybeToggle() {
 
   if (should_indicator_be_on != indicator_was_on) {
     was_recently_audible_ = should_indicator_be_on;
-    web_contents_->NotifyNavigationStateChanged(INVALIDATE_TYPE_TAB);
+    audible_change_callback_.Run(was_recently_audible_);
   }
 
   if (!should_indicator_be_on) {