diff --git a/test/fixtures/wpt/README.md b/test/fixtures/wpt/README.md
index 8f59b55ce8af85..074caa3d711cb7 100644
--- a/test/fixtures/wpt/README.md
+++ b/test/fixtures/wpt/README.md
@@ -13,7 +13,7 @@ Last update:
 - console: https://github.com/web-platform-tests/wpt/tree/3b1f72e99a/console
 - encoding: https://github.com/web-platform-tests/wpt/tree/3c9820d1cc/encoding
 - url: https://github.com/web-platform-tests/wpt/tree/1783c9bccf/url
-- resources: https://github.com/web-platform-tests/wpt/tree/001e50de41/resources
+- resources: https://github.com/web-platform-tests/wpt/tree/351a99782b/resources
 - interfaces: https://github.com/web-platform-tests/wpt/tree/8719553b2d/interfaces
 - html/webappapis/microtask-queuing: https://github.com/web-platform-tests/wpt/tree/2c5c3c4c27/html/webappapis/microtask-queuing
 - html/webappapis/timers: https://github.com/web-platform-tests/wpt/tree/264f12bc7b/html/webappapis/timers
diff --git a/test/fixtures/wpt/resources/testdriver-actions.js b/test/fixtures/wpt/resources/testdriver-actions.js
index f3e6388e8acd19..4dafa0c018b101 100644
--- a/test/fixtures/wpt/resources/testdriver-actions.js
+++ b/test/fixtures/wpt/resources/testdriver-actions.js
@@ -281,9 +281,12 @@
      *                               pointer source
      * @returns {Actions}
      */
-    pointerDown: function({button=this.ButtonType.LEFT, sourceName=null}={}) {
+    pointerDown: function({button=this.ButtonType.LEFT, sourceName=null,
+                           width, height, pressure, tangentialPressure,
+                           tiltX, tiltY, twist, altitudeAngle, azimuthAngle}={}) {
       let source = this.getSource("pointer", sourceName);
-      source.pointerDown(this, button);
+      source.pointerDown(this, button, width, height, pressure, tangentialPressure,
+                         tiltX, tiltY, twist, altitudeAngle, azimuthAngle);
       return this;
     },
 
@@ -314,9 +317,13 @@
      * @returns {Actions}
      */
     pointerMove: function(x, y,
-                          {origin="viewport", duration, sourceName=null}={}) {
+                          {origin="viewport", duration, sourceName=null,
+                           width, height, pressure, tangentialPressure,
+                           tiltX, tiltY, twist, altitudeAngle, azimuthAngle}={}) {
       let source = this.getSource("pointer", sourceName);
-      source.pointerMove(this, x, y, duration, origin);
+      source.pointerMove(this, x, y, duration, origin, width, height, pressure,
+                         tangentialPressure, tiltX, tiltY, twist, altitudeAngle,
+                         azimuthAngle);
       return this;
     },
 
@@ -424,6 +431,38 @@
     this.actions = new Map();
   }
 
+  function setPointerProperties(action, width, height, pressure, tangentialPressure,
+                                tiltX, tiltY, twist, altitudeAngle, azimuthAngle) {
+    if (width) {
+      action.width = width;
+    }
+    if (height) {
+      action.height = height;
+    }
+    if (pressure) {
+      action.pressure = pressure;
+    }
+    if (tangentialPressure) {
+      action.tangentialPressure = tangentialPressure;
+    }
+    if (tiltX) {
+      action.tiltX = tiltX;
+    }
+    if (tiltY) {
+      action.tiltY = tiltY;
+    }
+    if (twist) {
+      action.twist = twist;
+    }
+    if (altitudeAngle) {
+      action.altitudeAngle = altitudeAngle;
+    }
+    if (azimuthAngle) {
+      action.azimuthAngle = azimuthAngle;
+    }
+    return action;
+  }
+
   PointerSource.prototype = {
     serialize: function(tickCount) {
       if (!this.actions.size) {
@@ -441,12 +480,16 @@
       return data;
     },
 
-    pointerDown: function(actions, button) {
+    pointerDown: function(actions, button, width, height, pressure, tangentialPressure,
+                          tiltX, tiltY, twist, altitudeAngle, azimuthAngle) {
       let tick = actions.tickIdx;
       if (this.actions.has(tick)) {
         tick = actions.addTick().tickIdx;
       }
-      this.actions.set(tick, {type: "pointerDown", button});
+      let actionProperties = setPointerProperties({type: "pointerDown", button}, width, height,
+                                                  pressure, tangentialPressure, tiltX, tiltY,
+                                                  twist, altitudeAngle, azimuthAngle);
+      this.actions.set(tick, actionProperties);
     },
 
     pointerUp: function(actions, button) {
@@ -457,15 +500,20 @@
       this.actions.set(tick, {type: "pointerUp", button});
     },
 
-    pointerMove: function(actions, x, y, duration, origin) {
+    pointerMove: function(actions, x, y, duration, origin, width, height, pressure,
+                          tangentialPressure, tiltX, tiltY, twist, altitudeAngle, azimuthAngle) {
       let tick = actions.tickIdx;
       if (this.actions.has(tick)) {
         tick = actions.addTick().tickIdx;
       }
-      this.actions.set(tick, {type: "pointerMove", x, y, origin});
+      let moveAction = {type: "pointerMove", x, y, origin};
       if (duration) {
-        this.actions.get(tick).duration = duration;
+        moveAction.duration = duration;
       }
+      let actionProperties = setPointerProperties(moveAction, width, height, pressure,
+                                                  tangentialPressure, tiltX, tiltY, twist,
+                                                  altitudeAngle, azimuthAngle);
+      this.actions.set(tick, actionProperties);
     },
 
     addPause: function(actions, duration) {
diff --git a/test/fixtures/wpt/resources/testdriver.js b/test/fixtures/wpt/resources/testdriver.js
index c53b24136c091f..f3cee9821e13f9 100644
--- a/test/fixtures/wpt/resources/testdriver.js
+++ b/test/fixtures/wpt/resources/testdriver.js
@@ -146,6 +146,24 @@
                                                       y: centerPoint[1]});
         },
 
+        /**
+         * Deletes all cookies.
+         *
+         * This matches the behaviour of the {@link
+         * https://w3c.github.io/webdriver/#delete-all-cookies|WebDriver
+         * Delete All Cookies command}.
+         *
+         * @param {WindowProxy} context - Browsing context in which
+         *                                to run the call, or null for the current
+         *                                browsing context.
+         *
+         * @returns {Promise} fulfilled after cookies are deleted, or rejected in
+         *                    the cases the WebDriver command errors
+         */
+        delete_all_cookies: function(context=null) {
+            return window.test_driver_internal.delete_all_cookies(context);
+        },
+
         /**
          * Send keys to an element
          *
@@ -458,6 +476,10 @@
             });
         },
 
+        delete_all_cookies: function(context=null) {
+            return Promise.reject(new Error("unimplemented"));
+        },
+
         send_keys: function(element, keys) {
             if (this.in_automation) {
                 return Promise.reject(new Error('Not implemented'));
diff --git a/test/fixtures/wpt/resources/testharness.js b/test/fixtures/wpt/resources/testharness.js
index d50e094117df56..f7fe7531710d23 100644
--- a/test/fixtures/wpt/resources/testharness.js
+++ b/test/fixtures/wpt/resources/testharness.js
@@ -2956,22 +2956,16 @@ policies and contribution forms [3].
     }
 
     function sanitize_unpaired_surrogates(str) {
-        return str.replace(/([\ud800-\udbff])(?![\udc00-\udfff])/g,
-                           function(_, unpaired)
-                           {
-                               return code_unit_str(unpaired);
-                           })
-                  // This replacement is intentionally implemented without an
-                  // ES2018 negative lookbehind assertion to support runtimes
-                  // which do not yet implement that language feature.
-                  .replace(/(^|[^\ud800-\udbff])([\udc00-\udfff])/g,
-                           function(_, previous, unpaired) {
-                              if (/[\udc00-\udfff]/.test(previous)) {
-                                  previous = code_unit_str(previous);
-                              }
-
-                              return previous + code_unit_str(unpaired);
-                           });
+        return str.replace(
+            /([\ud800-\udbff]+)(?![\udc00-\udfff])|(^|[^\ud800-\udbff])([\udc00-\udfff]+)/g,
+            function(_, low, prefix, high) {
+                var output = prefix || "";  // prefix may be undefined
+                var string = low || high;  // only one of these alternates can match
+                for (var i = 0; i < string.length; i++) {
+                    output += code_unit_str(string[i]);
+                }
+                return output;
+            });
     }
 
     function sanitize_all_unpaired_surrogates(tests) {
@@ -3612,6 +3606,9 @@ policies and contribution forms [3].
 
     function AssertionError(message)
     {
+        if (typeof message == "string") {
+            message = sanitize_unpaired_surrogates(message);
+        }
         this.message = message;
         this.stack = this.get_stack();
     }
diff --git a/test/fixtures/wpt/versions.json b/test/fixtures/wpt/versions.json
index f5d2cc5c600658..b6a871ea9da93f 100644
--- a/test/fixtures/wpt/versions.json
+++ b/test/fixtures/wpt/versions.json
@@ -12,7 +12,7 @@
     "path": "url"
   },
   "resources": {
-    "commit": "001e50de41dc35820774b27e31f77a165f4c0b9b",
+    "commit": "351a99782b9677706b5dc0dd78e85978fa4ab130",
     "path": "resources"
   },
   "interfaces": {