diff --git a/dom/fetch/Headers.h b/dom/fetch/Headers.h
index a3810baa42b3..d52a25c222e8 100644
--- a/dom/fetch/Headers.h
+++ b/dom/fetch/Headers.h
@@ -102,6 +102,19 @@ public:
     mInternalHeaders->Set(aName, aValue, aRv);
   }
 
+  uint32_t GetIterableLength() const
+  {
+    return mInternalHeaders->GetIterableLength();
+  }
+  const nsString GetKeyAtIndex(unsigned aIndex) const
+  {
+    return mInternalHeaders->GetKeyAtIndex(aIndex);
+  }
+  const nsString GetValueAtIndex(unsigned aIndex) const
+  {
+    return mInternalHeaders->GetValueAtIndex(aIndex);
+  }
+
   // ChromeOnly
   HeadersGuardEnum Guard() const
   {
diff --git a/dom/fetch/InternalHeaders.h b/dom/fetch/InternalHeaders.h
index 9e11a1e102ec..d62b46fb57aa 100644
--- a/dom/fetch/InternalHeaders.h
+++ b/dom/fetch/InternalHeaders.h
@@ -70,6 +70,21 @@ public:
   bool Has(const nsACString& aName, ErrorResult& aRv) const;
   void Set(const nsACString& aName, const nsACString& aValue, ErrorResult& aRv);
 
+  uint32_t GetIterableLength() const
+  {
+    return mList.Length();
+  }
+  const NS_ConvertASCIItoUTF16 GetKeyAtIndex(unsigned aIndex) const
+  {
+    MOZ_ASSERT(aIndex < mList.Length());
+    return NS_ConvertASCIItoUTF16(mList[aIndex].mName);
+  }
+  const NS_ConvertASCIItoUTF16 GetValueAtIndex(unsigned aIndex) const
+  {
+    MOZ_ASSERT(aIndex < mList.Length());
+    return NS_ConvertASCIItoUTF16(mList[aIndex].mValue);
+  }
+
   void Clear();
 
   HeadersGuardEnum Guard() const { return mGuard; }
diff --git a/dom/tests/mochitest/fetch/test_headers_common.js b/dom/tests/mochitest/fetch/test_headers_common.js
index fca547bfcaeb..b82e5e224439 100644
--- a/dom/tests/mochitest/fetch/test_headers_common.js
+++ b/dom/tests/mochitest/fetch/test_headers_common.js
@@ -13,16 +13,27 @@ function shouldThrow(func, expected, msg) {
   }
 }
 
+function recursiveArrayCompare(actual, expected) {
+  is(Array.isArray(actual), Array.isArray(expected), "Both should either be arrays, or not");
+  if (Array.isArray(actual) && Array.isArray(expected)) {
+    var diff = actual.length !== expected.length;
+
+    for (var i = 0, n = actual.length; !diff && i < n; ++i) {
+      diff = recursiveArrayCompare(actual[i], expected[i]);
+    }
+
+    return diff;
+  } else {
+    return actual !== expected;
+  }
+}
+
 function arrayEquals(actual, expected, msg) {
   if (actual === expected) {
     return;
   }
 
-  var diff = actual.length !== expected.length;
-
-  for (var i = 0, n = actual.length; !diff && i < n; ++i) {
-    diff = actual[i] !== expected[i];
-  }
+  var diff = recursiveArrayCompare(actual, expected);
 
   ok(!diff, msg);
   if (diff) {
@@ -169,8 +180,60 @@ function TestFilledHeaders() {
   }, TypeError, "Fill with non-tuple sequence should throw TypeError.");
 }
 
+function iterate(iter) {
+  var result = [];
+  for (var val = iter.next(); !val.done;) {
+    result.push(val.value);
+    val = iter.next();
+  }
+  return result;
+}
+
+function iterateForOf(iter) {
+  var result = [];
+  for (var value of iter) {
+    result.push(value);
+  }
+  return result;
+}
+
+function byteInflate(str) {
+  var encoder = new TextEncoder("utf-8");
+  var encoded = encoder.encode(str);
+  var result = "";
+  for (var i = 0; i < encoded.length; ++i) {
+    result += String.fromCharCode(encoded[i]);
+  }
+  return result
+}
+
+function TestHeadersIterator() {
+  var ehsanInflated = byteInflate("احسان");
+  var headers = new Headers();
+  headers.set("foo0", "bar0");
+  headers.append("foo", "bar");
+  headers.append("foo", ehsanInflated);
+  headers.append("Foo2", "bar2");
+  headers.set("Foo2", "baz2");
+  headers.set("foo3", "bar3");
+  headers.delete("foo0");
+  headers.delete("foo3");
+
+  var key_iter = headers.keys();
+  var value_iter = headers.values();
+  var entries_iter = headers.entries();
+
+  arrayEquals(iterate(key_iter), ["foo", "foo", "foo2"], "Correct key iterator");
+  arrayEquals(iterate(value_iter), ["bar", ehsanInflated, "baz2"], "Correct value iterator");
+  arrayEquals(iterate(entries_iter), [["foo", "bar"], ["foo", ehsanInflated], ["foo2", "baz2"]], "Correct entries iterator");
+
+  arrayEquals(iterateForOf(headers), [["foo", "bar"], ["foo", ehsanInflated], ["foo2", "baz2"]], "Correct entries iterator");
+  arrayEquals(iterateForOf(new Headers(headers)), [["foo", "bar"], ["foo", ehsanInflated], ["foo2", "baz2"]], "Correct entries iterator");
+}
+
 function runTest() {
   TestEmptyHeaders();
   TestFilledHeaders();
+  TestHeadersIterator();
   return Promise.resolve();
 }
diff --git a/dom/webidl/Headers.webidl b/dom/webidl/Headers.webidl
index f27a1ec05411..38b0a3a2042b 100644
--- a/dom/webidl/Headers.webidl
+++ b/dom/webidl/Headers.webidl
@@ -27,6 +27,7 @@ interface Headers {
   [Throws] sequence<ByteString> getAll(ByteString name);
   [Throws] boolean has(ByteString name);
   [Throws] void set(ByteString name, ByteString value);
+  iterable<ByteString, ByteString>;
 
   // Used to test different guard states from mochitest.
   // Note: Must be set prior to populating headers or will throw.
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/__dir__.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/__dir__.ini
new file mode 100644
index 000000000000..e05911f92d2a
--- /dev/null
+++ b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/__dir__.ini
@@ -0,0 +1 @@
+prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-add.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-add.https.html.ini
deleted file mode 100644
index 2dc41a01c86e..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-add.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-add.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-delete.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-delete.https.html.ini
deleted file mode 100644
index 4deb7c866746..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-delete.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-delete.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-match.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-match.https.html.ini
deleted file mode 100644
index 55794621d5db..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-match.https.html.ini
+++ /dev/null
@@ -1,54 +0,0 @@
-[cache-match.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
-  [Cache.match and Cache.matchAll]
-    bug: https://github.com/w3c/web-platform-tests/issues/2098
-
-  [Cache.matchAll with URL]
-    expected: FAIL
-
-  [Cache.match with URL]
-    expected: FAIL
-
-  [Cache.matchAll with Request]
-    expected: FAIL
-
-  [Cache.match with Request]
-    expected: FAIL
-
-  [Cache.matchAll with new Request]
-    expected: FAIL
-
-  [Cache.match with new Request]
-    expected: FAIL
-
-  [Cache.matchAll with ignoreSearch option (request with no search parameters)]
-    expected: FAIL
-
-  [Cache.match with ignoreSearch option (request with no search parameters)]
-    expected: FAIL
-
-  [Cache.matchAll with ignoreSearch option (request with search parameter)]
-    expected: FAIL
-
-  [Cache.match with ignoreSearch option (request with search parameter)]
-    expected: FAIL
-
-  [Cache.matchAll with URL containing fragment]
-    expected: FAIL
-
-  [Cache.match with URL containing fragment]
-    expected: FAIL
-
-  [Cache.matchAll with responses containing "Vary" header]
-    expected: FAIL
-
-  [Cache.match with responses containing "Vary" header]
-    expected: FAIL
-
-  [Cache.matchAll with "ignoreVary" parameter]
-    expected: FAIL
-
-  [Cache.match with Request and Response objects with different URLs]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-put.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-put.https.html.ini
deleted file mode 100644
index 5bf731c6eda0..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-put.https.html.ini
+++ /dev/null
@@ -1,25 +0,0 @@
-[cache-put.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
-  [Cache.put with request URLs containing embedded credentials]
-    expected: FAIL
-    bug: https://github.com/w3c/web-platform-tests/issues/2098
-
-  [Cache.put called with Request and Response from fetch()]
-    expected: FAIL
-
-  [Cache.put with a Response containing an empty URL]
-    expected: FAIL
-
-  [Cache.put with HTTP 500 response]
-    expected: FAIL
-
-  [Cache.put called twice with matching Requests and different Responses]
-    expected: FAIL
-
-  [Cache.put called twice with request URLs that differ only by a fragment]
-    expected: FAIL
-
-  [Cache.put with a relative URL]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage-keys.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage-keys.https.html.ini
deleted file mode 100644
index bfd50d10e300..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage-keys.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-storage-keys.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage-match.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage-match.https.html.ini
deleted file mode 100644
index bcb1dbd46d26..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage-match.https.html.ini
+++ /dev/null
@@ -1,15 +0,0 @@
-[cache-storage-match.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
-  [CacheStorageMatch with no cache name provided]
-    expected: FAIL
-
-  [CacheStorageMatch from one of many caches]
-    expected: FAIL
-
-  [CacheStorageMatch from one of many caches by name]
-    expected: FAIL
-
-  [CacheStorageMatch a string request]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage.https.html.ini
deleted file mode 100644
index f651f5610ba9..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/serviceworker/cache-storage.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-storage.https.html]
-  type: testharness
-  prefs: [dom.serviceWorkers.enabled: true, dom.serviceWorkers.interception.enabled: true, dom.serviceWorkers.exemptFromPerDomainMax:true, dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/window/cache-match.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/window/cache-match.https.html.ini
deleted file mode 100644
index 564897b348fb..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/window/cache-match.https.html.ini
+++ /dev/null
@@ -1,52 +0,0 @@
-[cache-match.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
-  bug: https://github.com/w3c/web-platform-tests/issues/2098
-  [Cache.matchAll with URL]
-    expected: FAIL
-
-  [Cache.match with URL]
-    expected: FAIL
-
-  [Cache.matchAll with Request]
-    expected: FAIL
-
-  [Cache.match with Request]
-    expected: FAIL
-
-  [Cache.matchAll with new Request]
-    expected: FAIL
-
-  [Cache.match with new Request]
-    expected: FAIL
-
-  [Cache.matchAll with ignoreSearch option (request with no search parameters)]
-    expected: FAIL
-
-  [Cache.match with ignoreSearch option (request with no search parameters)]
-    expected: FAIL
-
-  [Cache.matchAll with ignoreSearch option (request with search parameter)]
-    expected: FAIL
-
-  [Cache.match with ignoreSearch option (request with search parameter)]
-    expected: FAIL
-
-  [Cache.matchAll with URL containing fragment]
-    expected: FAIL
-
-  [Cache.match with URL containing fragment]
-    expected: FAIL
-
-  [Cache.matchAll with responses containing "Vary" header]
-    expected: FAIL
-
-  [Cache.match with responses containing "Vary" header]
-    expected: FAIL
-
-  [Cache.matchAll with "ignoreVary" parameter]
-    expected: FAIL
-
-  [Cache.match with Request and Response objects with different URLs]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/window/cache-put.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/window/cache-put.https.html.ini
deleted file mode 100644
index f019ecc17cd5..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/window/cache-put.https.html.ini
+++ /dev/null
@@ -1,25 +0,0 @@
-[cache-put.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
-  [Cache.put with request URLs containing embedded credentials]
-    expected: FAIL
-    bug: https://github.com/w3c/web-platform-tests/issues/2098
-
-  [Cache.put called with Request and Response from fetch()]
-    expected: FAIL
-
-  [Cache.put with a Response containing an empty URL]
-    expected: FAIL
-
-  [Cache.put with HTTP 500 response]
-    expected: FAIL
-
-  [Cache.put called twice with matching Requests and different Responses]
-    expected: FAIL
-
-  [Cache.put called twice with request URLs that differ only by a fragment]
-    expected: FAIL
-
-  [Cache.put with a relative URL]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/window/cache-storage-match.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/window/cache-storage-match.https.html.ini
deleted file mode 100644
index 94db1d3279aa..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/window/cache-storage-match.https.html.ini
+++ /dev/null
@@ -1,15 +0,0 @@
-[cache-storage-match.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
-  [CacheStorageMatch with no cache name provided]
-    expected: FAIL
-
-  [CacheStorageMatch from one of many caches]
-    expected: FAIL
-
-  [CacheStorageMatch from one of many caches by name]
-    expected: FAIL
-
-  [CacheStorageMatch a string request]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/__dir__.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/__dir__.ini
new file mode 100644
index 000000000000..9f3cfaa25a0b
--- /dev/null
+++ b/testing/web-platform/meta/service-workers/cache-storage/worker/__dir__.ini
@@ -0,0 +1 @@
+prefs: [dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-add.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-add.https.html.ini
deleted file mode 100644
index f85c725a2220..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-add.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-add.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-delete.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-delete.https.html.ini
deleted file mode 100644
index 76859c63f047..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-delete.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-delete.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-match.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-match.https.html.ini
deleted file mode 100644
index 564897b348fb..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-match.https.html.ini
+++ /dev/null
@@ -1,52 +0,0 @@
-[cache-match.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
-  bug: https://github.com/w3c/web-platform-tests/issues/2098
-  [Cache.matchAll with URL]
-    expected: FAIL
-
-  [Cache.match with URL]
-    expected: FAIL
-
-  [Cache.matchAll with Request]
-    expected: FAIL
-
-  [Cache.match with Request]
-    expected: FAIL
-
-  [Cache.matchAll with new Request]
-    expected: FAIL
-
-  [Cache.match with new Request]
-    expected: FAIL
-
-  [Cache.matchAll with ignoreSearch option (request with no search parameters)]
-    expected: FAIL
-
-  [Cache.match with ignoreSearch option (request with no search parameters)]
-    expected: FAIL
-
-  [Cache.matchAll with ignoreSearch option (request with search parameter)]
-    expected: FAIL
-
-  [Cache.match with ignoreSearch option (request with search parameter)]
-    expected: FAIL
-
-  [Cache.matchAll with URL containing fragment]
-    expected: FAIL
-
-  [Cache.match with URL containing fragment]
-    expected: FAIL
-
-  [Cache.matchAll with responses containing "Vary" header]
-    expected: FAIL
-
-  [Cache.match with responses containing "Vary" header]
-    expected: FAIL
-
-  [Cache.matchAll with "ignoreVary" parameter]
-    expected: FAIL
-
-  [Cache.match with Request and Response objects with different URLs]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-put.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-put.https.html.ini
deleted file mode 100644
index f019ecc17cd5..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-put.https.html.ini
+++ /dev/null
@@ -1,25 +0,0 @@
-[cache-put.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
-  [Cache.put with request URLs containing embedded credentials]
-    expected: FAIL
-    bug: https://github.com/w3c/web-platform-tests/issues/2098
-
-  [Cache.put called with Request and Response from fetch()]
-    expected: FAIL
-
-  [Cache.put with a Response containing an empty URL]
-    expected: FAIL
-
-  [Cache.put with HTTP 500 response]
-    expected: FAIL
-
-  [Cache.put called twice with matching Requests and different Responses]
-    expected: FAIL
-
-  [Cache.put called twice with request URLs that differ only by a fragment]
-    expected: FAIL
-
-  [Cache.put with a relative URL]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage-keys.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage-keys.https.html.ini
deleted file mode 100644
index 823b5708433c..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage-keys.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-storage-keys.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage-match.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage-match.https.html.ini
deleted file mode 100644
index 94db1d3279aa..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage-match.https.html.ini
+++ /dev/null
@@ -1,15 +0,0 @@
-[cache-storage-match.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]
-  [CacheStorageMatch with no cache name provided]
-    expected: FAIL
-
-  [CacheStorageMatch from one of many caches]
-    expected: FAIL
-
-  [CacheStorageMatch from one of many caches by name]
-    expected: FAIL
-
-  [CacheStorageMatch a string request]
-    expected: FAIL
-
diff --git a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage.https.html.ini
deleted file mode 100644
index 6ed6d9d1af4a..000000000000
--- a/testing/web-platform/meta/service-workers/cache-storage/worker/cache-storage.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[cache-storage.https.html]
-  type: testharness
-  prefs: [dom.caches.enabled:true]