diff --git a/third_party/webkit/PerformanceTests/Speedometer/InteractiveRunner.html b/third_party/webkit/PerformanceTests/Speedometer/InteractiveRunner.html
index 3e6f078405f6..9cbfaa288993 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/InteractiveRunner.html
+++ b/third_party/webkit/PerformanceTests/Speedometer/InteractiveRunner.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
 <head>
-<title>Speedometer 2.0 Interactive Runner</title>
+<title>Speedometer 2.1 Interactive Runner</title>
 <script src="resources/benchmark-runner.js" defer></script>
 <script src="resources/tests.js" defer></script>
 <style>
diff --git a/third_party/webkit/PerformanceTests/Speedometer/README_MOZILLA b/third_party/webkit/PerformanceTests/Speedometer/README_MOZILLA
index 38e52424bf8e..de0cd8c20455 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/README_MOZILLA
+++ b/third_party/webkit/PerformanceTests/Speedometer/README_MOZILLA
@@ -1,8 +1,8 @@
 The source from this directory was copied from the
 PerformanceTests/Speedometer directory of the Webkit repository
-at: https://svn.webkit.org/repository/webkit/trunk
+at: https://svn.webkit.org/repository/webkit/trunk/PerformanceTests/Speedometer2.1/
 
-The SVN revision used was: 222778
+The SVN revision used was: 294153
 
 The contents of this directory are intended for use to "train" the
 profile guided optimization (PGO) of Firefox and for benchmarking
diff --git a/third_party/webkit/PerformanceTests/Speedometer/index.html b/third_party/webkit/PerformanceTests/Speedometer/index.html
index 010605225ea3..acac49d0f043 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/index.html
+++ b/third_party/webkit/PerformanceTests/Speedometer/index.html
@@ -2,7 +2,7 @@
 <html>
 <head>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-    <title>Speedometer 1.0</title>
+    <title>Speedometer 2.1</title>
     <link rel="stylesheet" href="resources/main.css">
     <script src="resources/main.js" defer></script>
     <script src="resources/benchmark-runner.js" defer></script>
@@ -20,7 +20,7 @@
             It uses demo web applications to simulate user actions such as adding to-do items.
         </p>
         <p id="screen-size-warning"><strong>
-            Your browser window is too small. For most accurate results, please make the viewport size at least 850px by 650px.<br>
+            Your browser window is too small. For most accurate results, please make the view port size at least 850px by 650px.<br>
             It's currently <span id="screen-size"></span>.
         </strong></p>
         <div class="buttons">
@@ -60,15 +60,17 @@
     </section>
 
     <section id="about">
-        <h1>About Speedometer</h1>
+        <h1>About Speedometer 2.1</h1>
 
-        <p>Speedometer measures simulated user interactions in web applications.</p>
+        <p>Speedometer tests a browser's Web app responsiveness by timing simulated user interactions.</p>
 
         <p>
-            The current benchmark uses TodoMVC to simulate user actions for adding, completing, and removing to-do items.
-            Speedometer repeats the same actions using DOM APIs &mdash;
-            a core set of web platform APIs used extensively in web applications &mdash;
-            as well as six popular JavaScript frameworks: Ember.js, Backbone.js, jQuery, AngularJS, React, and Flight.
+            This benchmark simulates user actions for adding, completing, and removing to-do items using multiple examples in TodoMVC.
+            Each example in TodoMVC implements the same todo application using DOM APIs in different ways.
+            Some call DOM APIs directly from ECMAScript 5 (ES5), ECMASCript 2015 (ES6), ES6 transpiled to ES5, and Elm transpiled to ES5.
+            Others use one of eleven popular JavaScript frameworks: React, React with Redux, Ember.js, Backbone.js,
+            AngularJS, (new) Angular, Vue.js, jQuery, Preact, Inferno, and Flight.
+
             Many of these frameworks are used on the most popular websites in the world, such as Facebook and Twitter.
             The performance of these types of operations depends on the speed of the DOM APIs, the JavaScript engine,
             CSS style resolution, layout, and other technologies.
@@ -82,17 +84,22 @@
         </p>
 
         <p>
-            Some browser engines use an optimization strategy of doing some work asynchronously to reduce the run time of synchronous operations.
+            Modern browser engines execute some work asynchronously as an optimization strategy to reduce the run time of synchronous operations.
             While returning control back to JavaScript execution as soon as possible is worth pursuing,
-            a holistic, accurate measurement of web application performance involves measuring
-            when these related, asynchronous computations actually complete.
-            Thus, Speedometer measures the time browser spends executing those asynchronous tasks in Speedometer,
-            estimated as the time between when a zero-second delay timer is scheduled and when it is fired.</p>
+            the run time cost of such an asynchronous work should still be taken into a holistic measurement of web application performance.
+            In addition, some modern JavaScript frameworks such as Vue.js and Preact call into DOM APIs asynchronously as an optimization technique.
+            Speedometer approximates the run time of this asynchronous work in the UI thread with a zero-second timer
+            that is scheduled immediately after each execution of synchronous operations.
+        </p>
+
+        <p>
+            Speedometer does not attempt to measure concurrent asynchronous work that does not directly impact the UI thread,
+            which tends not to affect app responsiveness.
+        </p>
 
         <p class="note">
-            <strong>Note:</strong> Speedometer is not meant to compare the performance of different JavaScript frameworks.
-            The mechanism we use to simulate user actions is different for each framework,
-            and we’re forcing frameworks to do more work synchronously than needed in some cases to ensure run time can be measured.
+            <strong>Note:</strong> Speedometer should not be used as a way to compare the performance of different JavaScript frameworks
+            as work load differs greatly in each framework.
         </p>
     </section>
 </main>
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/benchmark-runner.js b/third_party/webkit/PerformanceTests/Speedometer/resources/benchmark-runner.js
index 47cedfc09a4c..751992b4f190 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/benchmark-runner.js
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/benchmark-runner.js
@@ -49,8 +49,12 @@ BenchmarkRunner.prototype.waitForElement = function (selector) {
 
     function resolveIfReady() {
         var element = contentDocument.querySelector(selector);
-        if (element)
-            return promise.resolve(element);
+        if (element) {
+            window.requestAnimationFrame(function () {
+                return promise.resolve(element);
+            });
+            return;
+        }
         setTimeout(resolveIfReady, 50);
     }
 
@@ -142,7 +146,9 @@ BenchmarkRunner.prototype._runTest = function(suite, test, prepareReturnValue, c
         var endTime = now();
         self._frame.contentWindow._unusedHeightValue = height; // Prevent dead code elimination.
         self._writeMark(suite.name + '.' + test.name + '-async-end');
-        callback(syncTime, endTime - startTime, height);
+        window.requestAnimationFrame(function () {
+            callback(syncTime, endTime - startTime, height);
+        });
     }, 0);
 }
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/flightjs-example-app/app/css/custom.css b/third_party/webkit/PerformanceTests/Speedometer/resources/flightjs-example-app/app/css/custom.css
index 8fafae9a45df..697197a0757a 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/flightjs-example-app/app/css/custom.css
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/flightjs-example-app/app/css/custom.css
@@ -7,7 +7,7 @@
 table {
   -webkit-touch-callout: none;
   -webkit-user-select: none;
-  user-select: none;
+  -moz-user-select: none;
   -ms-user-select: none;
   user-select: none;
 }
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/main.css b/third_party/webkit/PerformanceTests/Speedometer/resources/main.css
index 3c8e10ceff5e..126cdcdbca34 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/main.css
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/main.css
@@ -214,8 +214,9 @@ section#detailed-results > .show-about {
 }
 
 section#about h1 {
-    margin-top: 20px;
-    font-size: 30px;
+    margin-top: 10px;
+    margin-bottom: 0px;
+    font-size: 25px;
 }
 
 section#about .note {
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angular/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angular/README.md
index 9934db3fb534..ac8b9f8ec401 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angular/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angular/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Angular 4 TodoMVC example
+# Speedometer 2.1: Angular 4 TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angularjs/readme.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angularjs/readme.md
index b60cab8609d4..977ca48965b1 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angularjs/readme.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/angularjs/readme.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Angular 1.6.5 TodoMVC example
+# Speedometer 2.1: Angular 1.6.5 TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/backbone/readme.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/backbone/readme.md
index c9bddfcb3499..b3d51c151392 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/backbone/readme.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/backbone/readme.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Backbone.js TodoMVC example
+# Speedometer 2.1: Backbone.js TodoMVC example
 
 ## Test locally
 
@@ -8,4 +8,4 @@
 
 ## Build
 
-There is no build step for this example.
\ No newline at end of file
+There is no build step for this example.
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/emberjs/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/emberjs/README.md
index b86348882a83..a5690cb30ee6 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/emberjs/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/emberjs/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Ember.js TodoMVC example
+# Speedometer 2.1: Ember.js TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/preact/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/preact/README.md
index 40a758a86e8a..064d171f0aa1 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/preact/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/preact/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Preact TodoMVC example
+# Speedometer 2.1: Preact TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react-redux/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react-redux/README.md
index ce7b8fd15804..ece240feb36b 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react-redux/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react-redux/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: React Redux TodoMVC example
+# Speedometer 2.1: React Redux TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react/README.md
index bc144e268064..e59579d5b769 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/react/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: React TodoMVC example
+# Speedometer 2.1: React TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/vuejs-cli/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/vuejs-cli/README.md
index a0279f4f3f5e..4b040950ff9c 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/vuejs-cli/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/architecture-examples/vuejs-cli/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Vue.js TodoMVC example
+# Speedometer 2.1: Vue.js TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015-babel-webpack/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015-babel-webpack/README.md
index 306ee077c4f9..f4e13738e22b 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015-babel-webpack/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015-babel-webpack/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: ES2015 + Babel + Webpack TodoMVC example
+# Speedometer 2.1: ES2015 + Babel + Webpack TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015/README.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015/README.md
index e9655887c74e..2134b4624fe8 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015/README.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/es2015/README.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: ES2015 TodoMVC example
+# Speedometer 2.1: ES2015 TodoMVC example
 
 ## Test locally
 
diff --git a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/vanillajs/readme.md b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/vanillajs/readme.md
index 85e9a23ee177..5d89f617eebe 100644
--- a/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/vanillajs/readme.md
+++ b/third_party/webkit/PerformanceTests/Speedometer/resources/todomvc/vanilla-examples/vanillajs/readme.md
@@ -1,4 +1,4 @@
-# Speedometer 2.0: Vanilla JavaScript TodoMVC example
+# Speedometer 2.1: Vanilla JavaScript TodoMVC example
 
 ## Test locally
 
