feat(perf): autoscale benchmarks depending on the browser.

modules/e2e_test_lib/e2e_test/perf_util.es6

@@ -7,19 +7,53 @@ module.exports = {
 };
 
 function runClickBenchmark(config) {
-  var url = encodeURI(config.url + '?' + config.params.map(function(param) {
-    return param.name + '=' + param.value;
-  }).join('&'));
-  browser.get(url);
-  var buttons = config.buttons.map(function(selector) {
-    return $(selector);
-  });
-  var benchmarkConfig = Object.create(browser.params.benchmark);
-  benchmarkConfig.id = browser.params.lang+'.'+config.id;
-  benchmarkConfig.params = config.params;
-  benchpress.runBenchmark(benchmarkConfig, function() {
-    buttons.forEach(function(button) {
-      button.click();
+  var globalParams = browser.params;
+  getScaleFactor(globalParams.benchmark.scaling).then(function(scaleFactor) {
+    var params = config.params.map(function(param) {
+      return {
+        name: param.name, value: applyScaleFactor(param.value, scaleFactor, param.scale)
+      }
+    });
+    var benchmarkConfig = Object.create(globalParams.benchmark);
+    benchmarkConfig.id = globalParams.lang+'.'+config.id;
+    benchmarkConfig.params = params;
+    benchmarkConfig.scaleFactor = scaleFactor;
+
+    var url = encodeURI(config.url + '?' + params.map(function(param) {
+      return param.name + '=' + param.value;
+    }).join('&'));
+    browser.get(url);
+    var buttons = config.buttons.map(function(selector) {
+      return $(selector);
+    });
+    benchpress.runBenchmark(benchmarkConfig, function() {
+      buttons.forEach(function(button) {
+        button.click();
+      });
     });
   });
+}
+
+function getScaleFactor(possibleScalings) {
+  return browser.executeScript('return navigator.userAgent').then(function(userAgent) {
+    var scaleFactor = 1;
+    possibleScalings.forEach(function(entry) {
+      if (userAgent.match(entry.userAgent)) {
+        scaleFactor = entry.value;
+      }
+    });
+    return scaleFactor;
+  });
+}
+
+function applyScaleFactor(value, scaleFactor, method) {
+  if (method === 'log2') {
+    return value + Math.log2(scaleFactor);
+  } else if (method === 'sqrt') {
+    return value * Math.sqrt(scaleFactor);
+  } else if (method === 'linear') {
+    return value * scaleFactor;
+  } else {
+    return value;
+  }
 }