Revert of Finalize migration of blink_perf.animation to smoothness.tough_animation_cases

PerformanceTests/Animation/resources/framerate.js

+(function(){
+
+var framesPerTimerReading = 10;
+var frameCount = 0;
+var startTime;
+var trackingFrameRate = false;
+
+function trackFrameRate(currTime)
+{
+    if (++frameCount == framesPerTimerReading) {
+        frameCount = 0;
+        PerfTestRunner.measureValueAsync(1000 * framesPerTimerReading / (currTime - startTime));
+        startTime = currTime;
+    }
+
+    if (trackingFrameRate)
+        requestAnimationFrame(trackFrameRate);
+}
+
+window.startTrackingFrameRate = function() {
+    if (trackingFrameRate)
+        return;
+    trackingFrameRate = true;
+    startTime = performance.now();
+    trackFrameRate();
+};
+
+window.stopTrackingFrameRate = function() {
+    trackingFrameRate = false;
+};
+
+})();