Add replace parameter to onclose stream callback.

This indicates that the stream is being replaced by another one with
the same id.  This avoids moving videos around when they are being
renegotiated.

static/galene.js

@@ -320,8 +320,9 @@ function gotClose(code, reason) {
  * @param {Stream} c
  */
 function gotDownStream(c) {
-    c.onclose = function() {
-        delMedia(c.id);
+    c.onclose = function(replace) {
+        if(!replace)
+            delMedia(c.id);
     };
     c.onerror = function(e) {
         console.error(e);
@@ -1013,11 +1014,16 @@ async function addLocalMedia(id) {
     }
 
     let old = id && serverConnection.up[id];
-    if(old)
-        old.close();
-
-    if(!audio && !video)
+    if(!audio && !video) {
+        if(old)
+            old.close();
         return;
+    }
+
+    if(old && old.onclose) {
+        // make sure that the camera is released before we try to reopen it
+        old.onclose.call(old, true);
+    }
 
     let constraints = {audio: audio, video: video};
     /** @type {MediaStream} */
@@ -1040,22 +1046,25 @@ async function addLocalMedia(id) {
         try {
             let f = new Filter(stream, filter);
             setFilter(c, f);
-            c.onclose = () => {
+            c.onclose = replace => {
                 stopStream(stream);
                 setFilter(c, null);
-                delMedia(c.id);
+                if(!replace)
+                    delMedia(c.id);
             }
         } catch(e) {
             displayWarning(e);
-            c.onclose = () => {
+            c.onclose = replace => {
                 stopStream(c.stream);
-                delMedia(c.id);
+                if(!replace)
+                    delMedia(c.id);
             }
         }
     } else {
-        c.onclose = () => {
+        c.onclose = replace => {
             stopStream(c.stream);
-            delMedia(c.id);
+            if(!replace)
+                delMedia(c.id);
         }
     }
 
@@ -1106,9 +1115,10 @@ async function addShareMedia() {
     let c = newUpStream();
     c.kind = 'screenshare';
     c.stream = stream;
-    c.onclose = () => {
+    c.onclose = replace => {
         stopStream(stream);
-        delMedia(c.id);
+        if(!replace)
+            delMedia(c.id);
     }
     stream.getTracks().forEach(t => {
         c.pc.addTrack(t, stream);
@@ -1141,7 +1151,7 @@ async function addFileMedia(file) {
     let c = newUpStream();
     c.kind = 'video';
     c.stream = stream;
-    c.onclose = function() {
+    c.onclose = function(replace) {
         stopStream(c.stream);
         let media = /** @type{HTMLVideoElement} */
             (document.getElementById('media-' + this.id));
@@ -1149,8 +1159,9 @@ async function addFileMedia(file) {
             URL.revokeObjectURL(media.src);
             media.src = null;
         }
-        delMedia(c.id);
-    }
+        if(!replace)
+            delMedia(c.id);
+    };
 
     stream.onaddtrack = function(e) {
         let t = e.track;

static/protocol.js

@@ -634,7 +634,7 @@ ServerConnection.prototype.gotAnswer = async function(id, sdp) {
             if(c.onerror)
                 c.onerror.call(c, e);
         } finally {
-            c.close(true);
+            c.close();
         }
         return;
     }
@@ -825,9 +825,10 @@ function Stream(sc, id, pc, up) {
     /* Callbacks */
 
     /**
-     * onclose is called when the stream is closed.
+     * onclose is called when the stream is closed.  Replace will be true
+     * if the stream is being replaced by another one with the same id.
      *
-     * @type{(this: Stream) => void}
+     * @type{(this: Stream, replace: boolean) => void}
      */
     this.onclose = null;
     /**
@@ -880,9 +881,10 @@ function Stream(sc, id, pc, up) {
  * streams in the down direction, this will be called automatically when
  * the server signals that it is closing a stream.
  *
- * @param {boolean} [nocallback]
+ * @param {boolean} [replace]
+ *    - true if the stream is being replaced by another one with the same id
  */
-Stream.prototype.close = function(nocallback) {
+Stream.prototype.close = function(replace) {
     let c = this;
 
     if(!c.sc) {
@@ -920,8 +922,8 @@ Stream.prototype.close = function(nocallback) {
     }
     c.sc = null;
 
-    if(!nocallback && c.onclose)
-        c.onclose.call(c);
+    if(c.onclose)
+        c.onclose.call(c, replace);
 };
 
 /**