Debugging for https://crbug.com/601435.

extensions/renderer/resources/serial_service.js

Index: extensions/renderer/resources/serial_service.js
diff --git a/extensions/renderer/resources/serial_service.js b/extensions/renderer/resources/serial_service.js
index 26b990b227e60d56c43385aa0e5ac39da21a5ee0..a8a082fa2b2f20afad1393dfd2904efd1b40741a 100644
--- a/extensions/renderer/resources/serial_service.js
+++ b/extensions/renderer/resources/serial_service.js
@@ -285,7 +285,15 @@ define('serial_service', [
     });
   };
 
+  var calls = 0;
   Connection.prototype.getControlSignals = function() {
+    // Creating this on any earlier call causes the handles to be lost and not
+    // cleaned up.
+    if (calls++ == 7) {
+      var pipe = core.createMessagePipe();
+      core.close(pipe.handle1);
+      core.close(pipe.handle0);
+    }
     return this.remoteConnection_.getControlSignals().then(function(result) {
       if (!result.signals)
         throw new Error('Failed to get control signals.');