DevTools: fix 'Failed to write into a temp file' when recording a filmstrip

Source/devtools/front_end/network/NetworkPanel.js

 /*
  * Copyright (C) 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2008, 2009 Anthony Ricaud <rik@webkit.org>
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 712 matching lines @@
     eventsRetrievalProgress: function(progress)
     {
     },
 
     startRecording: function()
     {
         if (this._target)
             return;
 
         this._target = WebInspector.targetManager.mainTarget();
-        this._tracingModel = new WebInspector.TracingModel(new WebInspector.TempFileBackingStorage("tracing"));
+        if (this._tracingModel)
+            this._tracingModel.reset();
+        else
+            this._tracingModel = new WebInspector.TracingModel(new WebInspector.TempFileBackingStorage("tracing"));
         this._target.tracingManager.start(this, "-*,disabled-by-default-devtools.screenshot", "");
         this._filmStripView.reset();
         this._filmStripView.setStatusText(WebInspector.UIString("Recording frames..."));
     },
 
     /**
      * @return {boolean}
      */
     isRecording: function()
     {
@@ skipping 28 matching lines @@
      * @param {!WebInspector.Context} context
      * @param {string} actionId
      */
     handleAction: function(context, actionId)
     {
         var panel = WebInspector.context.flavor(WebInspector.NetworkPanel);
         console.assert(panel && panel instanceof WebInspector.NetworkPanel);
         panel._toggleRecording();
     }
 }