Remove some unused and unneeded flags.

benchmarks/spinning-balls/v.js

 // Copyright 2011 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 24 matching lines @@
     return window.webkitRequestAnimationFrame ||
         window.mozRequestAnimationFrame ||
         window.oRequestAnimationFrame ||
         window.msRequestAnimationFrame ||
         function(callback, element) {
           window.setTimeout( callback, 1000 / 60 );
         };
   } )();
 }
 
+
+
+
 var kNPoints = 8000;
 var kNModifications = 20;
 var kNVisiblePoints = 200;
 var kDecaySpeed = 20;
 
 var kPointRadius = 4;
 var kInitialLifeForce = 100;
 
 var livePoints = void 0;
 var dyingPoints = void 0;
 var scene = void 0;
 var renderingStartTime = void 0;
+var omitFrameDueToVisibilityChange = false;
 var scene = void 0;
 var pausePlot = void 0;
 var splayTree = void 0;
 
+handleVisibilityChange();
+
+function handleVisibilityChange() {
+  console.log("visibility change");
+  omitFrameDueToVisibilityChange = true;
+  document.addEventListener("webkitvisibilitychange", handleVisibilityChange);
+  document.addEventListener("msvisibilitychange", handleVisibilityChange);
+  document.addEventListener("mozvisibilitychange", handleVisibilityChange);
+  document.addEventListener("visibilitychange", handleVisibilityChange);
+}
+
 
 function Point(x, y, z, payload) {
   this.x = x;
   this.y = y;
   this.z = z;
 
   this.next = null;
   this.prev = null;
   this.payload = payload;
   this.lifeForce = kInitialLifeForce;
@@ skipping 275 matching lines @@
 function render() {
   if (typeof renderingStartTime === 'undefined') {
     renderingStartTime = Date.now();
   }
 
   ModifyPointsSet();
 
   scene.draw();
 
   var renderingEndTime = Date.now();
-  var pause = renderingEndTime - renderingStartTime;
-  pausePlot.addPause(pause);
+  if (!omitFrameDueToVisibilityChange) {
+    var pause = renderingEndTime - renderingStartTime;
+    pausePlot.addPause(pause);
+  }
   renderingStartTime = renderingEndTime;
+  omitFrameDueToVisibilityChange = false;
 
   pausePlot.draw();
 
   div.innerHTML =
       livePoints.count + "/" + dyingPoints.count + " " +
       pause + "(max = " + pausePlot.maxPause + ") ms" ;
 
   // Schedule next frame.
   requestAnimationFrame(render);
 }
 
 
 function init() {
   livePoints = new PointsList;
   dyingPoints = new PointsList;
 
   splayTree = new SplayTree();
 
   scene = new Scene(640, 480);
 
   div = document.createElement("div");
   document.body.appendChild(div);
 
   pausePlot = new PausePlot(480, 240, 160);
 }
 
 
 init();
 render();