Bug 1565343 - Ignore alternate stacks for unknown kinds of channels, r=ochameau.

--HG--
extra : rebase_source : 915d492fc407c433fa33d4adf8fe914fd969267a

devtools/server/actors/network-monitor/stack-trace-collector.js

@@ -81,13 +81,19 @@ StackTraceCollector.prototype = {
     try {
       channel = subject.QueryInterface(Ci.nsIHttpChannel);
       id = channel.channelId;
-    } catch (e) {
+    } catch (e1) {
       // WebSocketChannels do not have IDs, so use the URL. When a WebSocket is
       // opened in a content process, a channel is created locally but the HTTP
       // channel for the connection lives entirely in the parent process. When
       // the server code running in the parent sees that HTTP channel, it will
       // look for the creation stack using the websocket's URL.
-      channel = subject.QueryInterface(Ci.nsIWebSocketChannel);
+      try {
+        channel = subject.QueryInterface(Ci.nsIWebSocketChannel);
+      } catch (e2) {
+        // Channels which don't implement the above interfaces can appear here,
+        // such as nsIFileChannel. Ignore these channels.
+        return;
+      }
       id = channel.URI.spec;
     }