Fix teardown of stale AudioStreamMonitor poll callbacks.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 7b92187af6915ddf3053944fb7756118b150e23a..9987d166e6ac23c65872f3e5777785c02fd4eb72 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -4394,6 +4394,8 @@ void WebContentsImpl::RenderViewTerminated(RenderViewHost* rvh,
   if (delegate_)
     delegate_->HideValidationMessage(this);
 
+  audio_stream_monitor_.RenderProcessGone(rvh->GetProcess()->GetID());
+
   // Reset the loading progress. TODO(avi): What does it mean to have a
   // "renderer crash" when there is more than one renderer process serving a
   // webpage? Once this function is called at a more granular frame level, we