Revive voronoi multi-threaded demo.

native_client_sdk/src/examples/demo/voronoi/example.js

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function moduleDidLoad() {
+}
+
+function postThreadFunc(numThreads) {
+  return function () {
+    common.naclModule.postMessage('threads: ' + numThreads);
+  }
+}
+
+// Add event listeners after the NaCl module has loaded.  These listeners will
+// forward messages to the NaCl module via postMessage()
+function attachListeners() {
+  document.getElementById('benchmark').addEventListener('click',
+    function() {
+      common.naclModule.postMessage('run benchmark');
+      common.updateStatus('BENCHMARKING... (please wait)');
+    });
+  document.getElementById('drawPoints').addEventListener('click',
+    function() {
+      var checked = document.getElementById('drawPoints').checked;
+      if (checked)
+        common.naclModule.postMessage('with points');
+      else
+        common.naclModule.postMessage('without points');
+    });
+  document.getElementById('drawInteriors').addEventListener('click',
+    function() {
+      var checked = document.getElementById('drawInteriors').checked;
+      if (checked)
+        common.naclModule.postMessage('with interiors');
+      else
+        common.naclModule.postMessage('without interiors');
+    });
+  var threads = [0, 1, 2, 4, 6, 8, 12, 16, 24, 32];
+  for (var i = 0; i < threads.length; i++) {
+    document.getElementById('radio'+i).addEventListener('click',
+        postThreadFunc(threads[i]));
+  }
+  document.getElementById('pointRange').addEventListener('change',
+    function() {
+      var value = document.getElementById('pointRange').value;
+      common.naclModule.postMessage('points: ' + value);
+      document.getElementById('pointCount').textContent = value + ' points';
+    });
+}
+
+// Handle a message coming from the NaCl module.
+// In the Voronoi example, the only message will be the benchmark result.
+function handleMessage(message_event) {
+  var x = (Math.round(message_event.data * 1000) / 1000).toFixed(3);
+  document.getElementById('result').textContent =
+    'Result: ' + x + ' seconds';
+  common.updateStatus('SUCCESS')
+}
+