diff --git a/testing/web-platform/meta/MANIFEST.json b/testing/web-platform/meta/MANIFEST.json
index 4cd8c7044f6c..2f859419ffc5 100644
--- a/testing/web-platform/meta/MANIFEST.json
+++ b/testing/web-platform/meta/MANIFEST.json
@@ -14681,6 +14681,10 @@
         "path": "hr-time/basic.html",
         "url": "/hr-time/basic.html"
       },
+      {
+        "path": "hr-time/basic.worker.js",
+        "url": "/hr-time/basic.worker"
+      },
       {
         "path": "hr-time/idlharness.html",
         "url": "/hr-time/idlharness.html"
@@ -26245,6 +26249,38 @@
         "path": "url/url-constructor.html",
         "url": "/url/url-constructor.html"
       },
+      {
+        "path": "url/urlsearchparams-append.html",
+        "url": "/url/urlsearchparams-append.html"
+      },
+      {
+        "path": "url/urlsearchparams-constructor.html",
+        "url": "/url/urlsearchparams-constructor.html"
+      },
+      {
+        "path": "url/urlsearchparams-delete.html",
+        "url": "/url/urlsearchparams-delete.html"
+      },
+      {
+        "path": "url/urlsearchparams-get.html",
+        "url": "/url/urlsearchparams-get.html"
+      },
+      {
+        "path": "url/urlsearchparams-getall.html",
+        "url": "/url/urlsearchparams-getall.html"
+      },
+      {
+        "path": "url/urlsearchparams-has.html",
+        "url": "/url/urlsearchparams-has.html"
+      },
+      {
+        "path": "url/urlsearchparams-set.html",
+        "url": "/url/urlsearchparams-set.html"
+      },
+      {
+        "path": "url/urlsearchparams-stringifier.html",
+        "url": "/url/urlsearchparams-stringifier.html"
+      },
       {
         "path": "user-timing/idlharness.html",
         "url": "/user-timing/idlharness.html"
@@ -35420,7 +35456,7 @@
       }
     ]
   },
-  "rev": "a5f15d6bdbeeec010465dc906e542873d64797ec",
+  "rev": "623c1536821f7536d8ee2859bbeaf0d9738ea707",
   "url_base": "/",
   "version": 2
 }
diff --git a/testing/web-platform/meta/mozilla-sync b/testing/web-platform/meta/mozilla-sync
index e9fb93bd84aa..cd459f33df32 100644
--- a/testing/web-platform/meta/mozilla-sync
+++ b/testing/web-platform/meta/mozilla-sync
@@ -1 +1 @@
-1e125923b6586c58492f54dc396e6cbfd09c6ae2
\ No newline at end of file
+f0cc59cdba5802f6981f9325129c4ac4f3c7b805
\ No newline at end of file
diff --git a/testing/web-platform/tests/.gitmodules b/testing/web-platform/tests/.gitmodules
index 787d28dde644..d4eafdcc4d1c 100644
--- a/testing/web-platform/tests/.gitmodules
+++ b/testing/web-platform/tests/.gitmodules
@@ -5,3 +5,4 @@
 [submodule "tools"]
 	path = tools
 	url = https://github.com/w3c/wpt-tools.git
+	ignore = dirty
\ No newline at end of file
diff --git a/testing/web-platform/tests/content-security-policy/blink-contrib/self-doesnt-match-blob.sub.html b/testing/web-platform/tests/content-security-policy/blink-contrib/self-doesnt-match-blob.sub.html
index 487e8881bddc..5f388622c417 100644
--- a/testing/web-platform/tests/content-security-policy/blink-contrib/self-doesnt-match-blob.sub.html
+++ b/testing/web-platform/tests/content-security-policy/blink-contrib/self-doesnt-match-blob.sub.html
@@ -31,6 +31,10 @@ connect-src 'self'; script-src 'self' 'unsafe-inline'; child-src 'self';
             worker.onmessage = function(event) {
                 alert_assert(event.data);
             };
+            worker.onerror = function(event) {
+                alert_assert('TEST COMPLETE');
+                event.preventDefault();
+            }
         } catch (e) {
             alert_assert('TEST COMPLETE');
         }
diff --git a/testing/web-platform/tests/content-security-policy/blink-contrib/star-doesnt-match-blob.sub.html b/testing/web-platform/tests/content-security-policy/blink-contrib/star-doesnt-match-blob.sub.html
index 57fec43b6bb0..fac12b52a65a 100644
--- a/testing/web-platform/tests/content-security-policy/blink-contrib/star-doesnt-match-blob.sub.html
+++ b/testing/web-platform/tests/content-security-policy/blink-contrib/star-doesnt-match-blob.sub.html
@@ -31,6 +31,10 @@ connect-src 'self'; script-src 'self' 'unsafe-inline'; child-src *;
             worker.onmessage = function(event) {
                 alert_assert(event.data);
             };
+            worker.onerror = function(event) {
+                event.preventDefault();
+                alert_assert('TEST COMPLETE');
+            }
         } catch (e) {
             alert_assert('TEST COMPLETE');
         }
diff --git a/testing/web-platform/tests/hr-time/basic.worker.js b/testing/web-platform/tests/hr-time/basic.worker.js
new file mode 100644
index 000000000000..6a9f7a3932a7
--- /dev/null
+++ b/testing/web-platform/tests/hr-time/basic.worker.js
@@ -0,0 +1,18 @@
+importScripts("/resources/testharness.js");
+
+test(function() {
+  assert_true((performance !== undefined), "WorkerGlobalScope.performance exists");
+  assert_equals((typeof performance.now), "function");
+}, "WorkerGlobalScope.performance.now() is a function");
+
+test(function() {
+  assert_true(performance.now() > 0);
+}, "WorkerGlobalScope.performance.now() returns a positive number");
+
+test(function() {
+    var now1 = performance.now();
+    var now2 = performance.now();
+    assert_true((now2-now1) >= 0);
+  }, "WorkerGlobalScope.performance.now() difference is not negative");
+
+done();
diff --git a/testing/web-platform/tests/mixed-content/generic/common.js b/testing/web-platform/tests/mixed-content/generic/common.js
index e02e52f6b49e..3881513b2f25 100644
--- a/testing/web-platform/tests/mixed-content/generic/common.js
+++ b/testing/web-platform/tests/mixed-content/generic/common.js
@@ -83,7 +83,8 @@ function setAttributes(el, attrs) {
 function bindEvents(element, resolveEventName, rejectEventName) {
   element.eventPromise = new Promise(function(resolve, reject) {
     element.addEventListener(resolveEventName  || "load", resolve);
-    element.addEventListener(rejectEventName || "error", reject);
+    element.addEventListener(rejectEventName || "error",
+                             function(e) { e.preventDefault(); reject(); } );
   });
 }
 
diff --git a/testing/web-platform/tests/tools/.gitignore b/testing/web-platform/tests/tools/.gitignore
index 7a8ba560c9ea..76cfc1005c3a 100644
--- a/testing/web-platform/tests/tools/.gitignore
+++ b/testing/web-platform/tests/tools/.gitignore
@@ -3,4 +3,4 @@
 *.sw[po]
 *~
 \#*
-
+runner/MANIFEST.json
diff --git a/testing/web-platform/tests/tools/manifest/item.py b/testing/web-platform/tests/tools/manifest/item.py
index 702682cd70e5..3dee3173bd0f 100644
--- a/testing/web-platform/tests/tools/manifest/item.py
+++ b/testing/web-platform/tests/tools/manifest/item.py
@@ -1,8 +1,18 @@
+import os
 import urlparse
 from abc import ABCMeta, abstractmethod, abstractproperty
 
 item_types = ["testharness", "reftest", "manual", "stub", "wdspec"]
 
+
+def from_os_path(path):
+    return path.replace(os.path.sep, "/")
+
+
+def to_os_path(path):
+    return path.replace("/", os.path.sep)
+
+
 def get_source_file(source_files, tests_root, manifest, path):
     def make_new():
         from sourcefile import SourceFile
@@ -17,6 +27,7 @@ def get_source_file(source_files, tests_root, manifest, path):
 
     return source_files[path]
 
+
 class ManifestItem(object):
     __metaclass__ = ABCMeta
 
@@ -58,7 +69,7 @@ class ManifestItem(object):
         return hash(self.key() + self.meta_key())
 
     def to_json(self):
-        return {"path": self.path}
+        return {"path": from_os_path(self.path)}
 
     @classmethod
     def from_json(self, manifest, tests_root, obj, source_files=None):
@@ -86,7 +97,8 @@ class URLManifestItem(ManifestItem):
 
     @classmethod
     def from_json(cls, manifest, tests_root, obj, source_files=None):
-        source_file = get_source_file(source_files, tests_root, manifest, obj["path"])
+        source_file = get_source_file(source_files, tests_root, manifest,
+                                      to_os_path(obj["path"]))
         return cls(source_file,
                    obj["url"],
                    url_base=manifest.url_base,
@@ -111,7 +123,8 @@ class TestharnessTest(URLManifestItem):
 
     @classmethod
     def from_json(cls, manifest, tests_root, obj, source_files=None):
-        source_file = get_source_file(source_files, tests_root, manifest, obj["path"])
+        source_file = get_source_file(source_files, tests_root, manifest,
+                                      to_os_path(obj["path"]))
         return cls(source_file,
                    obj["url"],
                    url_base=manifest.url_base,
@@ -147,7 +160,8 @@ class RefTest(URLManifestItem):
 
     @classmethod
     def from_json(cls, manifest, tests_root, obj, source_files=None):
-        source_file = get_source_file(source_files, tests_root, manifest, obj["path"])
+        source_file = get_source_file(source_files, tests_root, manifest,
+                                      to_os_path(obj["path"]))
         return cls(source_file,
                    obj["url"],
                    obj["references"],
@@ -171,5 +185,6 @@ class WebdriverSpecTest(ManifestItem):
 
     @classmethod
     def from_json(cls, manifest, tests_root, obj, source_files=None):
-        source_file = get_source_file(source_files, tests_root, manifest, obj["path"])
+        source_file = get_source_file(source_files, tests_root, manifest,
+                                      to_os_path(obj["path"]))
         return cls(source_file, manifest=manifest)
diff --git a/testing/web-platform/tests/url/resources/testharness-extras.js b/testing/web-platform/tests/url/resources/testharness-extras.js
new file mode 100644
index 000000000000..c812ca64d19b
--- /dev/null
+++ b/testing/web-platform/tests/url/resources/testharness-extras.js
@@ -0,0 +1,11 @@
+/*
+Extending the W3C testharness.js with locally useful functionality.
+*/
+
+function assert_type_error(f, msg) {
+    assert_throws(TypeError(), f, msg);
+}
+
+function assert_syntax_error(f, msg) {
+    assert_throws(SyntaxError(), f, msg);
+}
diff --git a/testing/web-platform/tests/url/urlsearchparams-append.html b/testing/web-platform/tests/url/urlsearchparams-append.html
new file mode 100644
index 000000000000..78a8986e1e59
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-append.html
@@ -0,0 +1,51 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-append">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', 'b');
+    assert_equals(params + '', 'a=b');
+    params.append('a', 'b');
+    assert_equals(params + '', 'a=b&a=b');
+    params.append('a', 'c');
+    assert_equals(params + '', 'a=b&a=b&a=c');
+}, 'Append same name');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('', '');
+    assert_equals(params + '', '=');
+    params.append('', '');
+    assert_equals(params + '', '=&=');
+}, 'Append empty strings');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append(null, null);
+    assert_equals(params + '', 'null=null');
+    params.append(null, null);
+    assert_equals(params + '', 'null=null&null=null');
+}, 'Append null');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('first', 1);
+    params.append('second', 2);
+    params.append('third', '');
+    params.append('first', 10);
+    assert_true(params.has('first'), 'Search params object has name "first"');
+    assert_equals(params.get('first'), '1', 'Search params object has name "first" with value "1"');
+    assert_equals(params.get('second'), '2', 'Search params object has name "second" with value "2"');
+    assert_equals(params.get('third'), '', 'Search params object has name "third" with value ""');
+    params.append('first', 10);
+    assert_equals(params.get('first'), '1', 'Search params object has name "first" with value "1"');
+}, 'Append multiple');
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/url/urlsearchparams-constructor.html b/testing/web-platform/tests/url/urlsearchparams-constructor.html
new file mode 100644
index 000000000000..e2d7b11c1007
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-constructor.html
@@ -0,0 +1,129 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#urlsearchparams">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams();
+    assert_equals(params + '', '');
+    params = new URLSearchParams('');
+    assert_equals(params + '', '');
+    params = new URLSearchParams('a=b');
+    assert_equals(params + '', 'a=b');
+    params = new URLSearchParams(params);
+    assert_equals(params + '', 'a=b');
+}, 'Basic URLSearchParams construction');
+
+test(function() {
+    assert_type_error(function () { URLSearchParams(); }, 'Failed to construct \'URLSearchParams\': Please use the \'new\' operator, this DOM object constructor cannot be called as a function.');
+    assert_type_error(function () { new URLSearchParams(DOMException.prototype); });
+    var params = new URLSearchParams('');
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_equals(params.__proto__, URLSearchParams.prototype, 'expected URLSearchParams.prototype as prototype.');
+    params = new URLSearchParams({});
+    assert_equals(params + '', '%5Bobject+Object%5D=');
+}, 'URLSearchParams constructor, empty.');
+
+test(function() {
+    var params = new URLSearchParams('a=b');
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_false(params.has('b'), 'Search params object has not got name "b"');
+    var params = new URLSearchParams('a=b&c');
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_true(params.has('c'), 'Search params object has name "c"');
+    var params = new URLSearchParams('&a&&& &&&&&a+b=& c&m%c3%b8%c3%b8');
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_true(params.has('a b'), 'Search params object has name "a b"');
+    assert_true(params.has(' '), 'Search params object has name " "');
+    assert_false(params.has('c'), 'Search params object did not have the name "c"');
+    assert_true(params.has(' c'), 'Search params object has name " c"');
+    assert_true(params.has('møø'), 'Search params object has name "møø"');
+}, 'URLSearchParams constructor, string.');
+
+test(function() {
+    var seed = new URLSearchParams('a=b&c=d');
+    var params = new URLSearchParams(seed);
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_equals(params.get('a'), 'b');
+    assert_equals(params.get('c'), 'd');
+    assert_false(params.has('d'));
+    // The name-value pairs are copied when created; later updates
+    // should not be observable.
+    seed.append('e', 'f');
+    assert_false(params.has('e'));
+    params.append('g', 'h');
+    assert_false(seed.has('g'));
+}, 'URLSearchParams constructor, object.');
+
+test(function() {
+    var params = new URLSearchParams('a=b+c');
+    assert_equals(params.get('a'), 'b c');
+    params = new URLSearchParams('a+b=c');
+    assert_equals(params.get('a b'), 'c');
+}, 'Parse +');
+
+test(function() {
+    var params = new URLSearchParams('a=b c');
+    assert_equals(params.get('a'), 'b c');
+    params = new URLSearchParams('a b=c');
+    assert_equals(params.get('a b'), 'c');
+}, 'Parse space');
+
+test(function() {
+    var params = new URLSearchParams('a=b%20c');
+    assert_equals(params.get('a'), 'b c');
+    params = new URLSearchParams('a%20b=c');
+    assert_equals(params.get('a b'), 'c');
+}, 'Parse %20');
+
+test(function() {
+    var params = new URLSearchParams('a=b\0c');
+    assert_equals(params.get('a'), 'b\0c');
+    params = new URLSearchParams('a\0b=c');
+    assert_equals(params.get('a\0b'), 'c');
+}, 'Parse \\0');
+
+test(function() {
+    var params = new URLSearchParams('a=b%00c');
+    assert_equals(params.get('a'), 'b\0c');
+    params = new URLSearchParams('a%00b=c');
+    assert_equals(params.get('a\0b'), 'c');
+}, 'Parse %00');
+
+test(function() {
+    var params = new URLSearchParams('a=b\u2384');
+    assert_equals(params.get('a'), 'b\u2384');
+    params = new URLSearchParams('a\u2384b=c');
+    assert_equals(params.get('a\u2384b'), 'c');
+}, 'Parse \u2384');  // Unicode Character 'COMPOSITION SYMBOL' (U+2384)
+
+test(function() {
+    var params = new URLSearchParams('a=b%e2%8e%84');
+    assert_equals(params.get('a'), 'b\u2384');
+    params = new URLSearchParams('a%e2%8e%84b=c');
+    assert_equals(params.get('a\u2384b'), 'c');
+}, 'Parse %e2%8e%84');  // Unicode Character 'COMPOSITION SYMBOL' (U+2384)
+
+test(function() {
+    var params = new URLSearchParams('a=b\uD83D\uDCA9c');
+    assert_equals(params.get('a'), 'b\uD83D\uDCA9c');
+    params = new URLSearchParams('a\uD83D\uDCA9b=c');
+    assert_equals(params.get('a\uD83D\uDCA9b'), 'c');
+}, 'Parse \uD83D\uDCA9');  // Unicode Character 'PILE OF POO' (U+1F4A9)
+
+test(function() {
+    var params = new URLSearchParams('a=b%f0%9f%92%a9c');
+    assert_equals(params.get('a'), 'b\uD83D\uDCA9c');
+    params = new URLSearchParams('a%f0%9f%92%a9b=c');
+    assert_equals(params.get('a\uD83D\uDCA9b'), 'c');
+}, 'Parse %f0%9f%92%a9');  // Unicode Character 'PILE OF POO' (U+1F4A9)
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/url/urlsearchparams-delete.html b/testing/web-platform/tests/url/urlsearchparams-delete.html
new file mode 100644
index 000000000000..f44de89e5417
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-delete.html
@@ -0,0 +1,42 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-delete">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams('a=b&c=d');
+    params.delete('a');
+    assert_equals(params + '', 'c=d');
+    params = new URLSearchParams('a=a&b=b&a=a&c=c');
+    params.delete('a');
+    assert_equals(params + '', 'b=b&c=c');
+    params = new URLSearchParams('a=a&=&b=b&c=c');
+    params.delete('');
+    assert_equals(params + '', 'a=a&b=b&c=c');
+    params = new URLSearchParams('a=a&null=null&b=b');
+    params.delete(null);
+    assert_equals(params + '', 'a=a&b=b');
+    params = new URLSearchParams('a=a&undefined=undefined&b=b');
+    params.delete(undefined);
+    assert_equals(params + '', 'a=a&b=b');
+}, 'Delete basics');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('first', 1);
+    assert_true(params.has('first'), 'Search params object has name "first"');
+    assert_equals(params.get('first'), '1', 'Search params object has name "first" with value "1"');
+    params.delete('first');
+    assert_false(params.has('first'), 'Search params object has no "first" name');
+    params.append('first', 1);
+    params.append('first', 10);
+    params.delete('first');
+    assert_false(params.has('first'), 'Search params object has no "first" name');
+}, 'Deleting appended multiple');
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/url/urlsearchparams-get.html b/testing/web-platform/tests/url/urlsearchparams-get.html
new file mode 100644
index 000000000000..ff8782561c36
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-get.html
@@ -0,0 +1,33 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-get">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams('a=b&c=d');
+    assert_equals(params.get('a'), 'b');
+    assert_equals(params.get('c'), 'd');
+    assert_equals(params.get('e'), null);
+    params = new URLSearchParams('a=b&c=d&a=e');
+    assert_equals(params.get('a'), 'b');
+    params = new URLSearchParams('=b&c=d');
+    assert_equals(params.get(''), 'b');
+    params = new URLSearchParams('a=&c=d&a=e');
+    assert_equals(params.get('a'), '');
+}, 'Get basics');
+
+test(function() {
+    var params = new URLSearchParams('first=second&third&&');
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_true(params.has('first'), 'Search params object has name "first"');
+    assert_equals(params.get('first'), 'second', 'Search params object has name "first" with value "second"');
+    assert_equals(params.get('third'), '', 'Search params object has name "third" with the empty value.');
+    assert_equals(params.get('fourth'), null, 'Search params object has no "fourth" name and value.');
+}, 'More get() basics');
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/url/urlsearchparams-getall.html b/testing/web-platform/tests/url/urlsearchparams-getall.html
new file mode 100644
index 000000000000..4285fa256398
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-getall.html
@@ -0,0 +1,37 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-getAll">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams('a=b&c=d');
+    assert_array_equals(params.getAll('a'), ['b']);
+    assert_array_equals(params.getAll('c'), ['d']);
+    assert_array_equals(params.getAll('e'), []);
+    params = new URLSearchParams('a=b&c=d&a=e');
+    assert_array_equals(params.getAll('a'), ['b', 'e']);
+    params = new URLSearchParams('=b&c=d');
+    assert_array_equals(params.getAll(''), ['b']);
+    params = new URLSearchParams('a=&c=d&a=e');
+    assert_array_equals(params.getAll('a'), ['', 'e']);
+}, 'getAll() basics');
+
+test(function() {
+    var params = new URLSearchParams('a=1&a=2&a=3&a');
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    var matches = params.getAll('a');
+    assert_true(matches && matches.length == 4, 'Search params object has values for name "a"');
+    assert_array_equals(matches, ['1', '2', '3', ''], 'Search params object has expected name "a" values');
+    params.set('a', 'one');
+    assert_equals(params.get('a'), 'one', 'Search params object has name "a" with value "one"');
+    var matches = params.getAll('a');
+    assert_true(matches && matches.length == 1, 'Search params object has values for name "a"');
+    assert_array_equals(matches, ['one'], 'Search params object has expected name "a" values');
+}, 'getAll() multiples');
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/url/urlsearchparams-has.html b/testing/web-platform/tests/url/urlsearchparams-has.html
new file mode 100644
index 000000000000..1e583c6cfcee
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-has.html
@@ -0,0 +1,36 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-has">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams('a=b&c=d');
+    assert_true(params.has('a'));
+    assert_true(params.has('c'));
+    assert_false(params.has('e'));
+    params = new URLSearchParams('a=b&c=d&a=e');
+    assert_true(params.has('a'));
+    params = new URLSearchParams('=b&c=d');
+    assert_true(params.has(''));
+    params = new URLSearchParams('null=a');
+    assert_true(params.has(null));
+}, 'Has basics');
+
+test(function() {
+    var params = new URLSearchParams('a=b&c=d&&');
+    params.append('first', 1);
+    params.append('first', 2);
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_true(params.has('c'), 'Search params object has name "c"');
+    assert_true(params.has('first'), 'Search params object has name "first"');
+    assert_false(params.has('d'), 'Search params object has no name "d"');
+    params.delete('first');
+    assert_false(params.has('first'), 'Search params object has no name "first"');
+}, 'has() following delete()');
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/url/urlsearchparams-set.html b/testing/web-platform/tests/url/urlsearchparams-set.html
new file mode 100644
index 000000000000..db0e7a67b757
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-set.html
@@ -0,0 +1,35 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-set">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams('a=b&c=d');
+    params.set('a', 'B');
+    assert_equals(params + '', 'a=B&c=d');
+    params = new URLSearchParams('a=b&c=d&a=e');
+    params.set('a', 'B');
+    assert_equals(params + '', 'a=B&c=d')
+    params.set('e', 'f');
+    assert_equals(params + '', 'a=B&c=d&e=f')
+}, 'Set basics');
+
+test(function() {
+    var params = new URLSearchParams('a=1&a=2&a=3');
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_equals(params.get('a'), '1', 'Search params object has name "a" with value "1"');
+    params.set('first', 4);
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_equals(params.get('a'), '1', 'Search params object has name "a" with value "1"');
+    params.set('a', 4);
+    assert_true(params.has('a'), 'Search params object has name "a"');
+    assert_equals(params.get('a'), '4', 'Search params object has name "a" with value "4"');
+}, 'URLSearchParams.set');
+</script>
+</head>
+</html>
+
diff --git a/testing/web-platform/tests/url/urlsearchparams-stringifier.html b/testing/web-platform/tests/url/urlsearchparams-stringifier.html
new file mode 100644
index 000000000000..4215a21a03b1
--- /dev/null
+++ b/testing/web-platform/tests/url/urlsearchparams-stringifier.html
@@ -0,0 +1,123 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf8">
+<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-set">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/testharness-extras.js"></script>
+<script>
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', 'b c');
+    assert_equals(params + '', 'a=b+c');
+    params.delete('a');
+    params.append('a b', 'c');
+    assert_equals(params + '', 'a+b=c');
+}, 'Serialize space');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', '');
+    assert_equals(params + '', 'a=');
+    params.append('a', '');
+    assert_equals(params + '', 'a=&a=');
+    params.append('', 'b');
+    assert_equals(params + '', 'a=&a=&=b');
+    params.append('', '');
+    assert_equals(params + '', 'a=&a=&=b&=');
+    params.append('', '');
+    assert_equals(params + '', 'a=&a=&=b&=&=');
+}, 'Serialize empty value');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('', 'b');
+    assert_equals(params + '', '=b');
+    params.append('', 'b');
+    assert_equals(params + '', '=b&=b');
+}, 'Serialize empty name');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('', '');
+    assert_equals(params + '', '=');
+    params.append('', '');
+    assert_equals(params + '', '=&=');
+}, 'Serialize empty name and value');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', 'b+c');
+    assert_equals(params + '', 'a=b%2Bc');
+    params.delete('a');
+    params.append('a+b', 'c');
+    assert_equals(params + '', 'a%2Bb=c');
+}, 'Serialize +');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('=', 'a');
+    assert_equals(params + '', '%3D=a');
+    params.append('b', '=');
+    assert_equals(params + '', '%3D=a&b=%3D');
+}, 'Serialize =');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('&', 'a');
+    assert_equals(params + '', '%26=a');
+    params.append('b', '&');
+    assert_equals(params + '', '%26=a&b=%26');
+}, 'Serialize &');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', '*-._');
+    assert_equals(params + '', 'a=*-._');
+    params.delete('a');
+    params.append('*-._', 'c');
+    assert_equals(params + '', '*-._=c');
+}, 'Serialize *-._');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', 'b%c');
+    assert_equals(params + '', 'a=b%25c');
+    params.delete('a');
+    params.append('a%b', 'c');
+    assert_equals(params + '', 'a%25b=c');
+}, 'Serialize %');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', 'b\0c');
+    assert_equals(params + '', 'a=b%00c');
+    params.delete('a');
+    params.append('a\0b', 'c');
+    assert_equals(params + '', 'a%00b=c');
+}, 'Serialize \\0');
+
+test(function() {
+    var params = new URLSearchParams();
+    params.append('a', 'b\uD83D\uDCA9c');
+    assert_equals(params + '', 'a=b%F0%9F%92%A9c');
+    params.delete('a');
+    params.append('a\uD83D\uDCA9b', 'c');
+    assert_equals(params + '', 'a%F0%9F%92%A9b=c');
+}, 'Serialize \uD83D\uDCA9');  // Unicode Character 'PILE OF POO' (U+1F4A9)
+
+test(function() {
+    var params;
+    params = new URLSearchParams('a=b&c=d&&e&&');
+    assert_equals(params.toString(), 'a=b&c=d&e=');
+    params = new URLSearchParams('a = b &a=b&c=d%20');
+    assert_equals(params.toString(), 'a+=+b+&a=b&c=d+');
+    // The lone '=' _does_ survive the roundtrip.
+    params = new URLSearchParams('a=&a=b');
+    assert_equals(params.toString(), 'a=&a=b');
+}, 'URLSearchParams.toString');
+</script>
+</head>
+</html>
+
diff --git a/testing/web-platform/tests/workers/Worker_cross_origin_security_err.htm b/testing/web-platform/tests/workers/Worker_cross_origin_security_err.htm
index 53e8a7b0537d..647a8b81e263 100644
--- a/testing/web-platform/tests/workers/Worker_cross_origin_security_err.htm
+++ b/testing/web-platform/tests/workers/Worker_cross_origin_security_err.htm
@@ -4,9 +4,14 @@
 <script src="/resources/testharnessreport.js"></script>
 <div id=log></div>
 <script>
-test(function() {
-  assert_throws("SECURITY_ERR", function() {
-    new Worker("ftp://example.org/support/WorkerBasic.js");
-  });
+async_test(function(t) {
+  try {
+    var w = new Worker("ftp://example.org/support/WorkerBasic.js");
+    w.onerror = t.step_func_done(function(e) {
+      assert_true(e instanceof ErrorEvent);
+    });
+  } catch (e) {
+    t.step_func_done(function(e) { assert_true(true); });
+  }
 });
 </script>
diff --git a/testing/web-platform/tests/workers/constructors/SharedWorker/same-origin.html b/testing/web-platform/tests/workers/constructors/SharedWorker/same-origin.html
index 196b53bedbe8..2e0dd8db33a7 100644
--- a/testing/web-platform/tests/workers/constructors/SharedWorker/same-origin.html
+++ b/testing/web-platform/tests/workers/constructors/SharedWorker/same-origin.html
@@ -12,35 +12,54 @@
 // not propogate to the window before the tests finish
 setup({allow_uncaught_exception: true});
 
+function testSharedWorkerHelper(t, script) {
+  try {
+    var worker = new SharedWorker(script, '');
+    worker.onerror = t.step_func_done(function(e) {
+      assert_true(e instanceof ErrorEvent);
+    });
+  } catch (e) {
+    t.step_func_done(function(e) { assert_true(true); });
+  }
+}
+
 test(function() {
   assert_throws("SecurityError", function() { new SharedWorker('unsupported:', ''); });
 }, "unsupported_scheme");
+
 async_test(function() {
   var worker = new SharedWorker('data:,onconnect = function(e) { e.ports[0].postMessage(1); }', '');
   worker.port.onmessage = this.step_func_done(function(e) {
     assert_equals(e.data, 1);
   });
 }, "data_url");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker('javascript:""', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, 'javascript:""');
 }, "javascript_url");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker('about:blank', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, 'about:blank');
 }, "about_blank");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker('http://www.opera.com/', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, 'http://www.opera.com/');
 }, "opera_com");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker(location.protocol+'//'+location.hostname+':81/', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, location.protocol+'//'+location.hostname+':81/');
 }, "port_81");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker('https://'+location.hostname+':80/', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, 'https://'+location.hostname+':80/');
 }, "https_port_80");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker('https://'+location.hostname+':8000/', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, 'https://'+location.hostname+':8000/');
 }, "https_port_8000");
-test(function() {
-  assert_throws("SecurityError", function() { new SharedWorker('http://'+location.hostname+':8012/', ''); });
+
+async_test(function(t) {
+  testSharedWorkerHelper(this, 'http://'+location.hostname+':8012/');
 }, "http_port_8012");
 </script>
 <!--
diff --git a/testing/web-platform/tests/workers/constructors/Worker/same-origin.html b/testing/web-platform/tests/workers/constructors/Worker/same-origin.html
index 0b4f2de5960a..9b0148da3a25 100644
--- a/testing/web-platform/tests/workers/constructors/Worker/same-origin.html
+++ b/testing/web-platform/tests/workers/constructors/Worker/same-origin.html
@@ -10,6 +10,17 @@
 // not propogate to the window before the tests finish
 setup({allow_uncaught_exception: true});
 
+function testSharedWorkerHelper(t, script) {
+  try {
+    var worker = new SharedWorker(script, '');
+    worker.onerror = t.step_func_done(function(e) {
+      assert_true(e instanceof ErrorEvent);
+    });
+  } catch (e) {
+    t.step_func_done(function(e) { assert_true(true); });
+  }
+}
+
 test(function() {
   assert_throws("SecurityError", function() { new Worker('unsupported:'); });
 }, "unsupported_scheme");
@@ -21,31 +32,32 @@ async_test(function() {
   });
 }, "data_url");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker('about:blank'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t, 'about:blank');
 }, "about_blank");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker('http://www.example.invalid/'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t, 'http://www.example.invalid/');
 }, "example_invalid");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker(location.protocol+'//'+location.hostname+':81/'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t, location.protocol+'//'+location.hostname+':81/');
 }, "port_81");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker('https://'+location.hostname+':80/'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t, 'https://'+location.hostname+':80/');
 }, "https_port_80");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker('https://'+location.hostname+':8000/'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t, 'https://'+location.hostname+':8000/');
 }, "https_port_8000");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker('http://'+location.hostname+':8012/'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t, 'http://'+location.hostname+':8012/');
 }, "http_post_8012");
 
-test(function() {
-  assert_throws("SecurityError", function() { new Worker('javascript:""'); });
+async_test(function(t) {
+  testSharedWorkerHelper(t,'javascript:""');
 }, "javascript_url");
+
 </script>