Add better consistency check and error output to plot script.

tools/profviz/worker.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 54 matching lines @@
 }
 
 
 function load_scripts(scripts) {
   time("Loading scripts",
        function() { for (var i in scripts) importScripts(scripts[i]); });
   self.postMessage({ "call" : "script" });
 }
 
 
+function log_error(text) {
+  self.postMessage({"call": "error", "args": text});
+  self.postMessage({"call": "reset"});
+}
+
+
 function run(args) {
   var file = args["file"];
   var resx = args["resx"];
   var resy = args["resy"];
   var distortion = args["distortion"];
   var range_start_override = args["range_start"];
   var range_end_override = args["range_end"];
 
   var reader = new FileReaderSync();
   var content_lines;
@@ skipping 29 matching lines @@
          for (var i = 0; i < content_lines.length; i++) {
            tickProcessor.processLogLine(content_lines[i]);
          }
          tickProcessor.printStatistics();
          displayprof(profile);
        });
 
   var input_file_name = "input_temp";
   var output_file_name = "output.svg";
 
-  var psc = new PlotScriptComposer(resx, resy);
+  var psc = new PlotScriptComposer(resx, resy, log_error);
   var objects = 0;
 
   time("Collecting events (" + content_lines.length + " entries)",
        function() {
          var line_cursor = 0;
          var input = function() { return content_lines[line_cursor++]; };
          psc.collectData(input, distortion);
          psc.findPlotRange(range_start_override,
                            range_end_override,
                            setRange);
@@ skipping 23 matching lines @@
 
 var Module = {
     "noInitialRun": true,
     print: function(text) {
         self.postMessage({"call": "error", "args": text});
     },
     printErr: function(text) {
         self.postMessage({"call": "error", "args": text});
     },
 };