Merge pull request #662 from jan-ivar/mustmute

Relinquish device when all tracks are muted or disabled.

getusermedia.html

@@ -725,6 +725,37 @@ <h4>Life-cycle</h4>
         provided the UA sets it back to <code>true</code> as soon as any
         unstopped track connected to this device becomes un-muted or enabled
         again.</p>
+        <p>When a <code>live</code>, <a href="#track-muted">unmuted</a>, and
+        <a href="#track-enabled">enabled</a> track sourced by a device exposed
+        by <a data-link-for="MediaDevices">getUserMedia()</a> becomes either
+        <a href="#track-muted">muted</a> or <a href="#track-enabled">disabled</a>,
+        and this brings <em>all</em> tracks connected to the device (regardless
+        of browsing context) to be either
+        muted, disabled, or stopped, then the UA SHOULD relinquish the device
+        within 3 seconds while allowing time for a reasonably-observant user to
+        become aware of the transition. The UA SHOULD attempt to reacquire the
+        device as soon as any <code>live</code> track sourced by the device
+        becomes both <a href="#track-muted">unmuted</a> and
+        <a href="#track-enabled">enabled</a> again, provided that track's
+        <a>current settings object</a>'s <a>responsible document</a>
+        <a data-cite="!HTML/#gains-focus">has focus</a> at that time. If the
+        document does not <a data-cite="!HTML/#gains-focus">have focus</a> at that time,
+        the UA SHOULD instead queue a task to <a href="#track-muted">mute</a> the
+        track, and not queue a task to <a href="#track-muted">unmute</a> it until
+        the document <a data-cite="!HTML/#gains-focus">regains focus</a>.
+        If reacquiring the device fails, the UA MUST
+        <a href="#ends-nostop">end the track</a> (The UA MAY end it earlier
+        should it detect a device problem, like the device being physically
+        removed).</p>
+        <div class="note">
+          <p>The intent is to give users the assurance of privacy that having
+          physical camera (and microphone) hardware lights off brings, by
+          aligning physical and logical “privacy indicators”, at least while the
+          current document is the sole user of a device.</p>
+          <p>While other applications and documents using the device
+          simultaneously may interfere with this intent at times, they do not
+          interfere with the rules laid forth.</p>
+        </div>
         <p>The muted/unmuted state of a track reflects whether the source
         provides any media at this moment. The enabled/disabled state is under
         application control and determines whether the track outputs media (to