mozilla-release: changeset 505623:7b845eac9dd726c7213024ccb94b009da5674592

--- a/accessible/tests/mochitest/elm/test_shadowroot.html
+++ b/accessible/tests/mochitest/elm/test_shadowroot.html
@@ -18,23 +18,19 @@
   </a><br/>
   <p id="display"></p>
   <div id="content" style="display: none"></div>
   <pre id="test">
   </pre>
 
   <script>
     SimpleTest.waitForExplicitFinish();
-    SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.webcomponents.shadowdom.enabled", true],
-      ],
-    }, function() {
-      // This test loads in an iframe, to ensure that the element instance is
-      // loaded with the correct value of the preference.
+
+    window.onload = () => {
       var iframe = document.createElement("iframe");
       iframe.src = "test_shadowroot_subframe.html";
       document.body.appendChild(iframe);
-    });
+    };
+
   </script>
 
 </body>
 </html>

--- a/accessible/tests/mochitest/hittest/test_shadowroot.html
+++ b/accessible/tests/mochitest/hittest/test_shadowroot.html
@@ -18,23 +18,19 @@
   </a><br/>
   <p id="display"></p>
   <div id="content" style="display: none"></div>
   <pre id="test">
   </pre>
 
   <script>
     SimpleTest.waitForExplicitFinish();
-    SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.webcomponents.shadowdom.enabled", true],
-      ],
-    }, function() {
-      // This test loads in an iframe, to ensure that the element instance is
-      // loaded with the correct value of the preference.
+
+    window.onload = () => {
       var iframe = document.createElement("iframe");
       iframe.src = "test_shadowroot_subframe.html";
       document.body.appendChild(iframe);
-    });
+    };
+
   </script>
 
 </body>
 </html>

--- a/accessible/tests/mochitest/relations/test_shadowdom.html
+++ b/accessible/tests/mochitest/relations/test_shadowdom.html
@@ -12,64 +12,48 @@
           src="../common.js"></script>
   <script type="application/javascript"
           src="../relations.js"></script>
   <script type="application/javascript"
           src="../role.js"></script>
 
   <script type="application/javascript">
     function doTest() {
-      let iframeDoc = document.getElementById("iframe").contentDocument;
-
       // explicit content
-      let label = iframeDoc.getElementById("label");
-      let element = iframeDoc.getElementById("element");
+      let label = document.getElementById("label");
+      let element = document.getElementById("element");
       testRelation(label, RELATION_LABEL_FOR, element);
       testRelation(element, RELATION_LABELLED_BY, label);
 
       // shadow DOM content
-      let shadowRoot = iframeDoc.getElementById("shadowcontainer").shadowRoot;
+      let shadowRoot = document.getElementById("shadowcontainer").shadowRoot;
       let shadowLabel = shadowRoot.getElementById("label");
       let shadowElement = shadowRoot.getElementById("element");
 
       testRelation(shadowLabel, RELATION_LABEL_FOR, shadowElement);
       testRelation(shadowElement, RELATION_LABELLED_BY, shadowLabel);
 
       SimpleTest.finish();
     }
 
     SimpleTest.waitForExplicitFinish();
-    SpecialPowers.pushPrefEnv({
-      set: [
-        [ "dom.webcomponents.shadowdom.enabled", true ],
-      ],
-    }, function() {
-      // This test loads in an iframe, to ensure that the element instance is
-      // loaded with the correct value of the preference.
-      let sc = "script";
-      let iframe = document.createElement("iframe");
-      iframe.id = "iframe";
-      iframe.src = `data:text/html,<html>
-        <body>
-          <div id='label'></div><div id='element' aria-labelledby='label'></div>
-          <div id='shadowcontainer'></div>
-          <${sc}>
-            let shadowRoot = document.getElementById('shadowcontainer').
-              attachShadow({mode: 'open'});
-            shadowRoot.innerHTML =
-              "<div id='label'></div><div id='element' aria-labelledby='label'></div>";
-          </${sc}>
-        </body>
-      </html>`;
 
-      addA11yLoadEvent(doTest, iframe.contentWindow);
-      document.body.appendChild(iframe);
-    });
+    addA11yLoadEvent(doTest, window);
   </script>
 </head>
 
 <body>
   <p id="display"></p>
-  <div id="content" style="display: none"></div>
+  <div id="content">
+    <div id="label"></div>
+    <div id="element" aria-labelledby="label"></div>
+    <div id="shadowcontainer"></div>
+    <script>
+      let shadowRoot = document.getElementById("shadowcontainer").
+        attachShadow({mode: "open"});
+      shadowRoot.innerHTML =
+        `<div id="label"></div><div id="element" aria-labelledby="label"></div>`;
+    </script>
+  </div>
   <pre id="test">
   </pre>
 </body>
 </html>

--- a/accessible/tests/mochitest/treeupdate/test_bug1276857.html
+++ b/accessible/tests/mochitest/treeupdate/test_bug1276857.html
@@ -109,27 +109,22 @@
     function doTest() {
       gQueue = new eventQueue();
       gQueue.push(new runTest());
       gQueue.push(new runShadowTest());
       gQueue.invoke(); // will call SimpleTest.finish();
     }
 
     SimpleTest.waitForExplicitFinish();
-    SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.webcomponents.shadowdom.enabled", true],
-      ],
-    }, function() {
-      // This test loads in an iframe, to ensure that the element instance is
-      // loaded with the correct value of the preference.
+
+    window.onload = () => {
       let iframe = document.createElement("iframe");
       iframe.id = "iframe";
       iframe.src = "test_bug1276857_subframe.html";
       addA11yLoadEvent(doTest, iframe.contentWindow);
       document.body.appendChild(iframe);
-    });
+    };
   </script>
 
 </head>
 <body>
 </body>
 </html>

--- a/browser/base/content/test/general/browser_contentAltClick.js
+++ b/browser/base/content/test/general/browser_contentAltClick.js
@@ -12,17 +12,16 @@
   */
 "use strict";
 
 ChromeUtils.defineModuleGetter(this, "Downloads",
                                "resource://gre/modules/Downloads.jsm");
 
 function setup() {
   Services.prefs.setBoolPref("browser.altClickSave", true);
-  Services.prefs.setBoolPref("dom.webcomponents.shadowdom.enabled", true);
 
   let testPage =
     "data:text/html," +
     '<p><a id="commonlink" href="http://mochi.test/moz/">Common link</a></p>' +
     '<p><math id="mathxlink" xmlns="http://www.w3.org/1998/Math/MathML" xlink:type="simple" xlink:href="http://mochi.test/moz/"><mtext>MathML XLink</mtext></math></p>' +
     '<p><svg id="svgxlink" xmlns="http://www.w3.org/2000/svg" width="100px" height="50px" version="1.1"><a xlink:type="simple" xlink:href="http://mochi.test/moz/"><text transform="translate(10, 25)">SVG XLink</text></a></svg></p><br>' +
     '<span id="host"></span><script>document.getElementById("host").attachShadow({mode: "closed"}).appendChild(document.getElementById("commonlink").cloneNode(true));</script>';
 
@@ -36,17 +35,16 @@ async function clean_up() {
   for (let download of downloads) {
     await downloadList.remove(download);
     await download.finalize(true);
   }
   // Remove download history.
   await PlacesUtils.history.clear();
 
   Services.prefs.clearUserPref("browser.altClickSave");
-  Services.prefs.clearUserPref("dom.webcomponents.shadowdom.enabled");
   BrowserTestUtils.removeTab(gBrowser.selectedTab);
 }
 
 add_task(async function test_alt_click() {
   await setup();
 
   let downloadList = await Downloads.getList(Downloads.ALL);
   let downloads = [];

--- a/browser/base/content/test/general/browser_contextmenu.js
+++ b/browser/base/content/test/general/browser_contextmenu.js
@@ -58,18 +58,16 @@ add_task(async function test_xul_text_li
   // Clean up so won't affect HTML element test cases
   lastElementSelector = null;
   gBrowser.removeCurrentTab();
 });
 
 // Below are test cases for HTML element
 
 add_task(async function test_setup_html() {
-  await pushPrefs(["dom.webcomponents.shadowdom.enabled", true]);
-
   let url = example_base + "subtst_contextmenu.html";
 
   await BrowserTestUtils.openNewForegroundTab(gBrowser, url);
 
   await ContentTask.spawn(gBrowser.selectedBrowser, null, async function() {
     let doc = content.document;
     let audioIframe = doc.querySelector("#test-audio-in-iframe");
     // media documents always use a <video> tag.

--- a/browser/components/extensions/test/browser/browser_ext_menus_replace_menu.js
+++ b/browser/components/extensions/test/browser/browser_ext_menus_replace_menu.js
@@ -21,18 +21,17 @@ function checkIsDefaultMenuItemVisible(v
 // - The usual extension filtering behavior (e.g. documentUrlPatterns and
 //   targetUrlPatterns) is still applied; some menu items are therefore hidden.
 // - Calling overrideContext({showDefaults:true}) causes the default menu items
 //   to be shown, but only after the extension's.
 // - overrideContext expires after the menu is opened once.
 // - overrideContext can be called from shadow DOM.
 add_task(async function overrideContext_in_extension_tab() {
   await SpecialPowers.pushPrefEnv({
-    set: [["dom.webcomponents.shadowdom.enabled", true],
-          ["security.allow_eval_with_system_principal", true]]});
+    set: [["security.allow_eval_with_system_principal", true]]});
 
   function extensionTabScript() {
     document.addEventListener("contextmenu", () => {
       browser.menus.overrideContext({});
       browser.test.sendMessage("oncontextmenu_in_dom_part_1");
     }, {once: true});
 
     let shadowRoot = document.getElementById("shadowHost").attachShadow({mode: "open"});

--- a/browser/components/extensions/test/browser/browser_ext_menus_targetElement_shadow.js
+++ b/browser/components/extensions/test/browser/browser_ext_menus_targetElement_shadow.js
@@ -1,20 +1,18 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
 const PAGE = "http://mochi.test:8888/browser/browser/components/extensions/test/browser/context.html";
 
 add_task(async function menuInShadowDOM() {
-  Services.prefs.setBoolPref("dom.webcomponents.shadowdom.enabled", true);
   Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
   registerCleanupFunction(() => {
-    Services.prefs.clearUserPref("dom.webcomponents.shadowdom.enabled");
     Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
   });
 
   let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
   gBrowser.selectedTab = tab;
 
   async function background() {
     browser.menus.onShown.addListener(async (info, tab) => {

--- a/devtools/client/inspector/markup/test/browser_markup_anonymous_03.js
+++ b/devtools/client/inspector/markup/test/browser_markup_anonymous_03.js
@@ -5,18 +5,16 @@ http://creativecommons.org/publicdomain/
 "use strict";
 
 // Test shadow DOM content in the markupview.
 // Note that many features are not yet enabled, but basic listing
 // of elements should be working.
 const TEST_URL = URL_ROOT + "doc_markup_anonymous.html";
 
 add_task(async function() {
-  Services.prefs.setBoolPref("dom.webcomponents.shadowdom.enabled", true);
-
   const {inspector} = await openInspectorForURL(TEST_URL);
 
   const shadowHostFront = await getNodeFront("#shadow", inspector.markup);
   is(shadowHostFront.numChildren, 3, "Children of the shadow host are correct");
 
   await inspector.markup.expandNode(shadowHostFront);
   await waitForMultipleChildrenUpdates(inspector);

--- a/devtools/client/inspector/markup/test/browser_markup_dragdrop_invalidNodes.js
+++ b/devtools/client/inspector/markup/test/browser_markup_dragdrop_invalidNodes.js
@@ -5,17 +5,16 @@
 "use strict";
 
 // Check that pseudo-elements, anonymous nodes and slotted nodes are not draggable.
 
 const TEST_URL = URL_ROOT + "doc_markup_dragdrop.html";
 
 add_task(async function() {
   await pushPref("devtools.inspector.showAllAnonymousContent", true);
-  await pushPref("dom.webcomponents.shadowdom.enabled", true);
   await pushPref("dom.webcomponents.customelements.enabled", true);
 
   const {inspector} = await openInspectorForURL(TEST_URL);
 
   info("Expanding nodes below #test");
   const parentFront = await getNodeFront("#test", inspector);
   await inspector.markup.expandNode(parentFront);
   await waitForMultipleChildrenUpdates(inspector);

--- a/devtools/client/inspector/markup/test/browser_markup_shadowdom_navigation.js
+++ b/devtools/client/inspector/markup/test/browser_markup_shadowdom_navigation.js
@@ -40,17 +40,16 @@ const TEST_DATA = [
   ["KEY_ArrowDown", "div", "slotted2"],
   ["KEY_ArrowDown", "slotted1"],
   ["KEY_ArrowRight", "slotted1"],
   ["KEY_ArrowDown", "slot1-child"],
   ["KEY_ArrowDown", "slotted2"],
 ];
 
 add_task(async function() {
-  await pushPref("dom.webcomponents.shadowdom.enabled", true);
   await pushPref("dom.webcomponents.customelements.enabled", true);
 
   const {inspector} = await openInspectorForURL(TEST_URL);
 
   info("Making sure the markup-view frame is focused");
   inspector.markup._frame.focus();
 
   info("Starting to iterate through the test data");

--- a/devtools/client/inspector/markup/test/head.js
+++ b/devtools/client/inspector/markup/test/head.js
@@ -27,17 +27,16 @@ SimpleTest.requestCompleteLog();
 // Services.prefs.setBoolPref("devtools.dump.emit", true);
 
 // Clear preferences that may be set during the course of tests.
 registerCleanupFunction(() => {
   Services.prefs.clearUserPref("devtools.dump.emit");
   Services.prefs.clearUserPref("devtools.inspector.htmlPanelOpen");
   Services.prefs.clearUserPref("devtools.inspector.sidebarOpen");
   Services.prefs.clearUserPref("devtools.markup.pagesize");
-  Services.prefs.clearUserPref("dom.webcomponents.shadowdom.enabled");
   Services.prefs.clearUserPref("devtools.inspector.showAllAnonymousContent");
 });
 
 /**
  * Some tests may need to import one or more of the test helper scripts.
  * A test helper script is simply a js file that contains common test code that
  * is either not common-enough to be in head.js, or that is located in a
  * separate directory.

--- a/devtools/client/inspector/rules/test/browser_rules_shadowdom_slot_rules.js
+++ b/devtools/client/inspector/rules/test/browser_rules_shadowdom_slot_rules.js
@@ -31,17 +31,16 @@ const TEST_URL = `data:text/html;charset
       }
     });
   </script>
   </body>
   </html>
 `);
 
 add_task(async function() {
-  await pushPref("dom.webcomponents.shadowdom.enabled", true);
   await pushPref("dom.webcomponents.customelements.enabled", true);
 
   const {inspector} = await openInspectorForURL(TEST_URL);
   const {markup} = inspector;
   const ruleview = inspector.getPanel("ruleview").view;
 
   // <test-component> is a shadow host.
   info("Find and expand the test-component shadow DOM host.");

--- a/devtools/client/inspector/test/browser_inspector_breadcrumbs_shadowdom.js
+++ b/devtools/client/inspector/test/browser_inspector_breadcrumbs_shadowdom.js
@@ -18,17 +18,16 @@ const TEST_URL = `data:text/html;charset
         super();
         let shadowRoot = this.attachShadow({mode: 'open'});
         shadowRoot.innerHTML = '<slot class="slot-class" name="slot1"></slot>';
       }
     });
   </script>`;
 
 add_task(async function() {
-  await pushPref("dom.webcomponents.shadowdom.enabled", true);
   await pushPref("dom.webcomponents.customelements.enabled", true);
 
   const {inspector} = await openInspectorForURL(TEST_URL);
   const {markup} = inspector;
   const breadcrumbs = inspector.panelDoc.getElementById("inspector-breadcrumbs");
 
   info("Find and expand the test-component shadow DOM host.");
   const hostFront = await getNodeFront("test-component", inspector);

--- a/devtools/client/locales/en-US/inspector.properties
+++ b/devtools/client/locales/en-US/inspector.properties
@@ -87,17 +87,16 @@ markupView.custom.tooltiptext=Show custo
 # This is used to speak the New Attribute button when editing a tag
 # and a screen reader user tabs to it. This string is not visible onscreen.
 markupView.newAttribute.label=New attribute
 
 # LOCALIZATION NOTE (markupView.revealLink.tooltip)
 # Used as a tooltip for an icon in the markup view when displaying elements inserted in
 # <slot> nodes in a custom  component. When clicking on the icon, the corresponding
 # non-slotted container will be selected
-# (test with dom.webcomponents.shadowdom.enabled set to true)
 markupView.revealLink.tooltip=Reveal
 
 #LOCALIZATION NOTE: Used in the image preview tooltip when the image could not be loaded
 previewTooltip.image.brokenImage=Could not load the image
 
 # LOCALIZATION NOTE: Used in color picker tooltip when the eyedropper is disabled for
 # non-HTML documents
 eyedropper.disabled.title=Unavailable in non-HTML documents

--- a/devtools/client/shared/test/shared-head.js
+++ b/devtools/client/shared/test/shared-head.js
@@ -719,17 +719,16 @@ async function injectEventUtilsInContent
       "chrome://mochikit/content/tests/SimpleTest/EventUtils.js", EventUtils);
   });
 }
 
 /**
  * Temporarily flip all the preferences needed to enable web components.
  */
 async function enableWebComponents() {
-  await pushPref("dom.webcomponents.shadowdom.enabled", true);
   await pushPref("dom.webcomponents.customelements.enabled", true);
 }
 
 /*
  * Register an actor in the content process of the current tab.
  *
  * Calling ActorRegistry.registerModule only registers the actor in the current process.
  * As all test scripts are ran in the parent process, it is only registered here.

--- a/devtools/server/tests/mochitest/test_inspector-anonymous.html
+++ b/devtools/server/tests/mochitest/test_inspector-anonymous.html
@@ -16,19 +16,16 @@ https://bugzilla.mozilla.org/show_bug.cg
 window.onload = function() {
   const {DocumentWalker: _documentWalker} =
     require("devtools/server/actors/inspector/document-walker");
 
   const nodeFilterConstants =
     require("devtools/shared/dom-node-filter-constants");
   const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
-  SpecialPowers.pushPrefEnv({"set": [
-    ["dom.webcomponents.shadowdom.enabled", true],
-  ]});
   SimpleTest.waitForExplicitFinish();
 
   let gWalker = null;
   let gInspectee = null;
 
   addTest(async function setup() {
     info("Setting up inspector and walker actors.");

--- a/dom/base/ChildIterator.cpp
+++ b/dom/base/ChildIterator.cpp
@@ -20,18 +20,17 @@ namespace dom {
 ExplicitChildIterator::ExplicitChildIterator(const nsIContent* aParent,
                                              bool aStartAtBeginning)
   : mParent(aParent),
     mChild(nullptr),
     mDefaultChild(nullptr),
     mIsFirst(aStartAtBeginning),
     mIndexInInserted(0)
 {
-  mParentAsSlot = nsDocument::IsShadowDOMEnabled(mParent) ?
-    HTMLSlotElement::FromNode(mParent) : nullptr;
+  mParentAsSlot = HTMLSlotElement::FromNode(mParent);
 }
 
 nsIContent*
 ExplicitChildIterator::GetNextChild()
 {
   // If we're already in the inserted-children array, look there first
   if (mIndexInInserted) {
     MOZ_ASSERT(mChild);

--- a/dom/base/DocumentOrShadowRoot.cpp
+++ b/dom/base/DocumentOrShadowRoot.cpp
@@ -177,20 +177,16 @@ DocumentOrShadowRoot::GetRetargetedFocus
                                            getter_AddRefs(focusedWindow));
     // be safe and make sure the element is from this document
     if (focusedContent && focusedContent->OwnerDoc() == AsNode().OwnerDoc()) {
       if (focusedContent->ChromeOnlyAccess()) {
         focusedContent = focusedContent->FindFirstNonChromeOnlyAccessContent();
       }
 
       if (focusedContent) {
-        if (!nsDocument::IsShadowDOMEnabled(focusedContent)) {
-          return focusedContent->AsElement();
-        }
-
         if (nsIContent* retarget = Retarget(focusedContent)) {
           return retarget->AsElement();
         }
       }
     }
   }
 
   return nullptr;

--- a/dom/base/crashtests/1324463.html
+++ b/dom/base/crashtests/1324463.html
@@ -1,12 +1,11 @@
 <!DOCTYPE html>
 <html>
 <script>
-// requires: user_pref("dom.webcomponents.shadowdom.enabled", true);
 addEventListener("DOMContentLoaded", function(){
   let o_0 = document.createElement("span").attachShadow({ mode: "open" });
   let o_1 = document.createElementNS("http://www.mozilla.org/xbl", "binding");
   let o_2 = document.createElementNS("http://www.mozilla.org/xbl", "children");
   let o_3 = document.createTextNode("");
   o_0.appendChild(o_1);
   o_1.appendChild(o_2);
   o_2.appendChild(o_3);

deleted file mode 100644
--- a/dom/base/crashtests/1422931.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<!DOCTYPE html>
-<html>
-<body>
-<!-- Testing slot element with "dom.webcomponents.shadowdom.enabled" set to false -->
-<slot><div></div></slot>
-</html>

--- a/dom/base/crashtests/crashtests.list
+++ b/dom/base/crashtests/crashtests.list
@@ -186,27 +186,27 @@ load 852381.html
 load 863950.html
 load 864448.html
 load 886213.html
 load 898906.html
 load 930250.html
 load 942979.html
 load 973401.html
 load 978646.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1024428-1.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1027461-1.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1029710.html
+load 1024428-1.html
+load 1027461-1.html
+load 1029710.html
 load 1154598.xhtml
 load 1157995.html
 load 1158412.html
 load 1181619.html
 load 1230422.html
 load 1251361.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1281715.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1281745.html
+load 1281715.html
+load 1281745.html
 load 1304437.html
 pref(dom.IntersectionObserver.enabled,true) load 1324209.html
 load 1324500.html
 pref(dom.IntersectionObserver.enabled,true) load 1326194-1.html
 pref(dom.IntersectionObserver.enabled,true) load 1326194-2.html
 pref(dom.IntersectionObserver.enabled,true) load 1332939.html
 pref(dom.webcomponents.customelements.enabled,true) load 1341693.html
 load 1352453.html
@@ -226,24 +226,23 @@ load 1383780.html
 pref(clipboard.autocopy,true) load 1385272-1.html
 load 1393806.html
 load 1396466.html
 load 1397795.html
 load 1400701.html
 load 1403377.html
 load 1405771.html
 load 1406109-1.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1324463.html
+load 1324463.html
 pref(dom.webcomponents.customelements.enabled,true) load 1413815.html
 load 1411473.html
-pref(dom.webcomponents.shadowdom.enabled,false) load 1422931.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1419799.html
+load 1419799.html
 skip-if(!browserIsRemote) pref(dom.webcomponents.customelements.enabled,true) pref(dom.disable_open_during_load,false) load 1419902.html # skip on non e10s loads, Bug 1419902
-pref(dom.webcomponents.shadowdom.enabled,true) load 1422883.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1428053.html
+load 1422883.html
+load 1428053.html
 pref(dom.webcomponents.customelements.enabled,true) load 1441029.html
 load 1449601.html
 load 1445670.html
 load 1458016.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1459688.html
+load 1459688.html
 load 1460794.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1505875.html
+load 1505875.html
 pref(dom.webcomponents.customelements.enabled,true) load 1505811.html

--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -298,17 +298,16 @@ bool nsContentUtils::sTrustedFullscreenO
 bool nsContentUtils::sIsCutCopyAllowed = true;
 bool nsContentUtils::sIsUpgradableDisplayContentPrefEnabled = false;
 bool nsContentUtils::sIsFrameTimingPrefEnabled = false;
 bool nsContentUtils::sIsPerformanceTimingEnabled = false;
 bool nsContentUtils::sIsResourceTimingEnabled = false;
 bool nsContentUtils::sIsPerformanceNavigationTimingEnabled = false;
 bool nsContentUtils::sIsFormAutofillAutocompleteEnabled = false;
 bool nsContentUtils::sIsUAWidgetEnabled = false;
-bool nsContentUtils::sIsShadowDOMEnabled = false;
 bool nsContentUtils::sIsCustomElementsEnabled = false;
 bool nsContentUtils::sSendPerformanceTimingNotifications = false;
 bool nsContentUtils::sUseActivityCursor = false;
 bool nsContentUtils::sAnimationsAPICoreEnabled = false;
 bool nsContentUtils::sGetBoxQuadsEnabled = false;
 bool nsContentUtils::sSkipCursorMoveForSameValueSet = false;
 bool nsContentUtils::sRequestIdleCallbackEnabled = false;
 bool nsContentUtils::sLowerNetworkPriority = false;
@@ -669,19 +668,16 @@ nsContentUtils::Init()
                                "dom.enable_frame_timing", false);
 
   Preferences::AddBoolVarCache(&sIsFormAutofillAutocompleteEnabled,
                                "dom.forms.autocomplete.formautofill", false);
 
   Preferences::AddBoolVarCache(&sIsUAWidgetEnabled,
                                "dom.ua_widget.enabled", false);
 
-  Preferences::AddBoolVarCache(&sIsShadowDOMEnabled,
-                               "dom.webcomponents.shadowdom.enabled", false);
-
   Preferences::AddBoolVarCache(&sIsCustomElementsEnabled,
                                "dom.webcomponents.customelements.enabled", false);
 
   Preferences::AddIntVarCache(&sPrivacyMaxInnerWidth,
                               "privacy.window.maxInnerWidth",
                               1000);
 
   Preferences::AddIntVarCache(&sPrivacyMaxInnerHeight,

--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -3234,20 +3234,17 @@ public:
    * dom.ua_widget.enabled.
    *
    * When enabled, UA Widget will replace legacy XBL when rendering JS-implemented
    * web content widgets (videocontrols/datetimebox/etc.)
    *
    * It is really enabled only if Shadow DOM is also enabled.
    */
   static bool
-  IsUAWidgetEnabled() { return sIsShadowDOMEnabled && sIsUAWidgetEnabled; }
-
-  static bool
-  IsShadowDOMEnabled() { return sIsShadowDOMEnabled; }
+  IsUAWidgetEnabled() { return sIsUAWidgetEnabled; }
 
   /**
    * Returns true if reserved key events should be prevented from being sent
    * to their target. Instead, the key event should be handled by chrome only.
    */
   static bool ShouldBlockReservedKeys(mozilla::WidgetKeyboardEvent* aKeyEvent);
 
   /**
@@ -3550,17 +3547,16 @@ private:
   static uint32_t sHandlingInputTimeout;
   static bool sIsPerformanceTimingEnabled;
   static bool sIsResourceTimingEnabled;
   static bool sIsPerformanceNavigationTimingEnabled;
   static bool sIsUpgradableDisplayContentPrefEnabled;
   static bool sIsFrameTimingPrefEnabled;
   static bool sIsFormAutofillAutocompleteEnabled;
   static bool sIsUAWidgetEnabled;
-  static bool sIsShadowDOMEnabled;
   static bool sIsCustomElementsEnabled;
   static bool sSendPerformanceTimingNotifications;
   static bool sUseActivityCursor;
   static bool sAnimationsAPICoreEnabled;
   static bool sGetBoxQuadsEnabled;
   static bool sSkipCursorMoveForSameValueSet;
   static bool sRequestIdleCallbackEnabled;
   static bool sLowerNetworkPriority;

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -1410,17 +1410,16 @@ nsIDocument::nsIDocument()
     mDidFireDOMContentLoaded(true),
     mHasScrollLinkedEffect(false),
     mFrameRequestCallbacksScheduled(false),
     mIsTopLevelContentDocument(false),
     mIsContentDocument(false),
     mDidCallBeginLoad(false),
     mAllowPaymentRequest(false),
     mEncodingMenuDisabled(false),
-    mIsShadowDOMEnabled(false),
     mIsSVGGlyphsDocument(false),
     mInDestructor(false),
     mIsGoingAway(false),
     mInXBLUpdate(false),
     mNeedsReleaseAfterStackRefCntRelease(false),
     mStyleSetFilled(false),
     mSSApplicableStateNotificationPending(false),
     mMayHaveTitleElement(false),
@@ -2132,21 +2131,16 @@ nsDocument::Init()
   // mNodeInfo keeps NodeInfoManager alive!
   mNodeInfo = mNodeInfoManager->GetDocumentNodeInfo();
   NS_ENSURE_TRUE(mNodeInfo, NS_ERROR_OUT_OF_MEMORY);
   MOZ_ASSERT(mNodeInfo->NodeType() == DOCUMENT_NODE,
              "Bad NodeType in aNodeInfo");
 
   NS_ASSERTION(OwnerDoc() == this, "Our nodeinfo is busted!");
 
-  // Set this when document is initialized and value stays the same for the
-  // lifetime of the document.
-  mIsShadowDOMEnabled = nsContentUtils::IsShadowDOMEnabled() ||
-    (XRE_IsParentProcess() && AllowXULXBL());
-
   // If after creation the owner js global is not set for a document
   // we use the default compartment for this document, instead of creating
   // wrapper in some random compartment when the document is exposed to js
   // via some events.
   nsCOMPtr<nsIGlobalObject> global = xpc::NativeGlobal(xpc::PrivilegedJunkScope());
   NS_ENSURE_TRUE(global, NS_ERROR_FAILURE);
   mScopeObject = do_GetWeakReference(global);
   MOZ_ASSERT(mScopeObject);
@@ -2651,49 +2645,24 @@ WarnIfSandboxIneffective(nsIDocShell* aD
 }
 
 bool
 nsIDocument::IsSynthesized() {
   nsCOMPtr<nsILoadInfo> loadInfo = mChannel ? mChannel->GetLoadInfo() : nullptr;
   return loadInfo && loadInfo->GetServiceWorkerTaintingSynthesized();
 }
 
-bool
-nsDocument::IsShadowDOMEnabled(JSContext* aCx, JSObject* aGlobal)
-{
-  MOZ_DIAGNOSTIC_ASSERT(JS_IsGlobalObject(aGlobal));
-  nsCOMPtr<nsPIDOMWindowInner> window = xpc::WindowOrNull(aGlobal);
-
-  nsIDocument* doc = window ? window->GetExtantDoc() : nullptr;
-  if (!doc) {
-    return false;
-  }
-
-  return doc->IsShadowDOMEnabled();
-}
-
 // static
 bool
-nsDocument::IsShadowDOMEnabledAndCallerIsChromeOrAddon(JSContext* aCx,
-                                                       JSObject* aObject)
-{
-  if (IsShadowDOMEnabled(aCx, aObject)) {
-    nsIPrincipal* principal = nsContentUtils::SubjectPrincipal(aCx);
-    return principal &&
-      (nsContentUtils::IsSystemPrincipal(principal) ||
-       principal->GetIsAddonOrExpandedAddonPrincipal());
-  }
-
-  return false;
-}
-
-bool
-nsDocument::IsShadowDOMEnabled(const nsINode* aNode)
-{
-  return aNode->OwnerDoc()->IsShadowDOMEnabled();
+nsDocument::IsCallerChromeOrAddon(JSContext* aCx, JSObject* aObject)
+{
+  nsIPrincipal* principal = nsContentUtils::SubjectPrincipal(aCx);
+  return principal &&
+    (nsContentUtils::IsSystemPrincipal(principal) ||
+     principal->GetIsAddonOrExpandedAddonPrincipal());
 }
 
 nsresult
 nsDocument::StartDocumentLoad(const char* aCommand, nsIChannel* aChannel,
                               nsILoadGroup* aLoadGroup,
                               nsISupports* aContainer,
                               nsIStreamListener **aDocListener,
                               bool aReset, nsIContentSink* aSink)

--- a/dom/base/nsDocument.h
+++ b/dom/base/nsDocument.h
@@ -191,22 +191,19 @@ public:
   {
     return DocumentOrShadowRoot::GetValueMissingState(aName);
   }
   virtual void SetValueMissingState(const nsAString& aName, bool aValue) override
   {
     return DocumentOrShadowRoot::SetValueMissingState(aName, aValue);
   }
 
-  // Check whether shadow DOM is enabled for aGlobal.
-  static bool IsShadowDOMEnabled(JSContext* aCx, JSObject* aGlobal);
   // Check whether shadow DOM is enabled for the document this node belongs to.
   // Same as above, but also checks that the caller is either chrome or some addon.
-  static bool IsShadowDOMEnabledAndCallerIsChromeOrAddon(JSContext* aCx, JSObject* aObject);
-  static bool IsShadowDOMEnabled(const nsINode* aNode);
+  static bool IsCallerChromeOrAddon(JSContext* aCx, JSObject* aObject);
 
 public:
   using mozilla::dom::DocumentOrShadowRoot::GetElementById;
   using mozilla::dom::DocumentOrShadowRoot::GetElementsByTagName;
   using mozilla::dom::DocumentOrShadowRoot::GetElementsByTagNameNS;
   using mozilla::dom::DocumentOrShadowRoot::GetElementsByClassName;
 
   // EventTarget

--- a/dom/base/nsFocusManager.cpp
+++ b/dom/base/nsFocusManager.cpp
@@ -3514,57 +3514,55 @@ nsFocusManager::GetNextTabbableContent(n
   if (!startContent)
     return NS_OK;
 
   nsIContent* currentTopLevelHost = GetTopLevelHost(aStartContent);
 
   LOGCONTENTNAVIGATION("GetNextTabbable: %s", aStartContent);
   LOGFOCUSNAVIGATION(("  tabindex: %d", aCurrentTabIndex));
 
-  if (nsDocument::IsShadowDOMEnabled(aRootContent)) {
-    // If aStartContent is a shadow host or slot in forward navigation,
-    // search in scope owned by aStartContent
-    if (aForward && IsHostOrSlot(aStartContent)) {
-      nsIContent* contentToFocus =
-        GetNextTabbableContentInScope(aStartContent, aStartContent,
-                                      aOriginalStartContent, aForward,
-                                      aForward ? 1 : 0, aIgnoreTabIndex,
-                                      aForDocumentNavigation,
-                                      true /* aSkipOwner */);
-      if (contentToFocus) {
-        NS_ADDREF(*aResultContent = contentToFocus);
-        return NS_OK;
-      }
+  // If aStartContent is a shadow host or slot in forward navigation,
+  // search in scope owned by aStartContent
+  if (aForward && IsHostOrSlot(aStartContent)) {
+    nsIContent* contentToFocus =
+      GetNextTabbableContentInScope(aStartContent, aStartContent,
+                                    aOriginalStartContent, aForward,
+                                    aForward ? 1 : 0, aIgnoreTabIndex,
+                                    aForDocumentNavigation,
+                                    true /* aSkipOwner */);
+    if (contentToFocus) {
+      NS_ADDREF(*aResultContent = contentToFocus);
+      return NS_OK;
     }
-
-    // If aStartContent is not in a scope owned by the root element
-    // (i.e. aStartContent is already in shadow DOM),
-    // search from scope including aStartContent
-    nsIContent* rootElement = aRootContent->OwnerDoc()->GetRootElement();
-    nsIContent* owner = FindOwner(aStartContent);
-    if (owner && rootElement != owner) {
-      nsIContent* contentToFocus =
-        GetNextTabbableContentInAncestorScopes(&aStartContent,
-                                               aOriginalStartContent,
-                                               aForward,
-                                               &aCurrentTabIndex,
-                                               aIgnoreTabIndex,
-                                               aForDocumentNavigation);
-      if (contentToFocus) {
-        NS_ADDREF(*aResultContent = contentToFocus);
-        return NS_OK;
-      }
+  }
+
+  // If aStartContent is not in a scope owned by the root element
+  // (i.e. aStartContent is already in shadow DOM),
+  // search from scope including aStartContent
+  nsIContent* rootElement = aRootContent->OwnerDoc()->GetRootElement();
+  nsIContent* owner = FindOwner(aStartContent);
+  if (owner && rootElement != owner) {
+    nsIContent* contentToFocus =
+      GetNextTabbableContentInAncestorScopes(&aStartContent,
+                                             aOriginalStartContent,
+                                             aForward,
+                                             &aCurrentTabIndex,
+                                             aIgnoreTabIndex,
+                                             aForDocumentNavigation);
+    if (contentToFocus) {
+      NS_ADDREF(*aResultContent = contentToFocus);
+      return NS_OK;
     }
-
-    // If we reach here, it means no next tabbable content in shadow DOM.
-    // We need to continue searching in light DOM, starting at the shadow host
-    // in light DOM (updated aStartContent) and its tabindex
-    // (updated aCurrentTabIndex).
   }
 
+  // If we reach here, it means no next tabbable content in shadow DOM.
+  // We need to continue searching in light DOM, starting at the shadow host
+  // in light DOM (updated aStartContent) and its tabindex
+  // (updated aCurrentTabIndex).
+
   nsPresContext* presContext = aPresShell->GetPresContext();
 
   bool getNextFrame = true;
   nsCOMPtr<nsIContent> iterStartContent = aStartContent;
   while (1) {
     nsIFrame* startFrame = iterStartContent->GetPrimaryFrame();
     // if there is no frame, look for another content node that has a frame
     if (!startFrame) {
@@ -3692,18 +3690,17 @@ nsFocusManager::GetNextTabbableContent(n
 
       // As of now, 2018/04/12, sequential focus navigation is still
       // in the obsolete Shadow DOM specification.
       // http://w3c.github.io/webcomponents/spec/shadow/#sequential-focus-navigation
       // "if ELEMENT is focusable, a shadow host, or a slot element,
       //  append ELEMENT to NAVIGATION-ORDER."
       // and later in "For each element ELEMENT in NAVIGATION-ORDER: "
       // hosts and slots are handled before other elements.
-      if (currentContent && nsDocument::IsShadowDOMEnabled(currentContent) &&
-          IsHostOrSlot(currentContent)) {
+      if (currentContent && IsHostOrSlot(currentContent)) {
         bool focusableHostSlot;
         int32_t tabIndex = HostOrSlotTabIndexValue(currentContent,
                                                    &focusableHostSlot);
         // Host or slot itself isn't focusable, enter its scope.
         if (!focusableHostSlot &&
             tabIndex >= 0 &&
             (aIgnoreTabIndex || aCurrentTabIndex == tabIndex)) {
           nsIContent* contentToFocus =
@@ -3793,32 +3790,30 @@ nsFocusManager::GetNextTabbableContent(n
             // Also, when going backwards, check to ensure that the focus
             // wouldn't be redirected. Otherwise, for example, when an input in
             // a textbox is focused, the enclosing textbox would be found and
             // the same inner input would be returned again.
             else if (currentContent == aRootContent ||
                      (currentContent != startContent &&
                       (aForward || !GetRedirectedFocus(currentContent)))) {
 
-              if (nsDocument::IsShadowDOMEnabled(aRootContent)) {
-                // If currentContent is a shadow host in backward
-                // navigation, search in scope owned by currentContent
-                if (!aForward && currentContent->GetShadowRoot()) {
-                  nsIContent* contentToFocus =
-                    GetNextTabbableContentInScope(currentContent,
-                                                  currentContent,
-                                                  aOriginalStartContent,
-                                                  aForward, aForward ? 1 : 0,
-                                                  aIgnoreTabIndex,
-                                                  aForDocumentNavigation,
-                                                  true /* aSkipOwner */);
-                  if (contentToFocus) {
-                    NS_ADDREF(*aResultContent = contentToFocus);
-                    return NS_OK;
-                  }
+              // If currentContent is a shadow host in backward
+              // navigation, search in scope owned by currentContent
+              if (!aForward && currentContent->GetShadowRoot()) {
+                nsIContent* contentToFocus =
+                  GetNextTabbableContentInScope(currentContent,
+                                                currentContent,
+                                                aOriginalStartContent,
+                                                aForward, aForward ? 1 : 0,
+                                                aIgnoreTabIndex,
+                                                aForDocumentNavigation,
+                                                true /* aSkipOwner */);
+                if (contentToFocus) {
+                  NS_ADDREF(*aResultContent = contentToFocus);
+                  return NS_OK;
                 }
               }
 
               NS_ADDREF(*aResultContent = currentContent);
               return NS_OK;
             }
           }
         }
@@ -3990,17 +3985,17 @@ nsFocusManager::GetNextTabIndex(nsIConte
 
   if (aForward) {
     tabIndex = 0;
     for (nsIContent* child = iter.GetNextChild();
          child;
          child = iter.GetNextChild()) {
       // Skip child's descendants if child is a shadow host or slot, as they are
       // in the focus navigation scope owned by child's shadow root
-      if (!(nsDocument::IsShadowDOMEnabled(aParent) && IsHostOrSlot(child))) {
+      if (!IsHostOrSlot(child)) {
         childTabIndex = GetNextTabIndex(child, aCurrentTabIndex, aForward);
         if (childTabIndex > aCurrentTabIndex && childTabIndex != tabIndex) {
           tabIndex = (tabIndex == 0 || childTabIndex < tabIndex) ? childTabIndex : tabIndex;
         }
       }
 
       nsAutoString tabIndexStr;
       if (child->IsElement()) {
@@ -4015,17 +4010,17 @@ nsFocusManager::GetNextTabIndex(nsIConte
   }
   else { /* !aForward */
     tabIndex = 1;
     for (nsIContent* child = iter.GetNextChild();
          child;
          child = iter.GetNextChild()) {
       // Skip child's descendants if child is a shadow host or slot, as they are
       // in the focus navigation scope owned by child's shadow root
-      if (!(nsDocument::IsShadowDOMEnabled(aParent) && IsHostOrSlot(child))) {
+      if (!IsHostOrSlot(child)) {
         childTabIndex = GetNextTabIndex(child, aCurrentTabIndex, aForward);
         if ((aCurrentTabIndex == 0 && childTabIndex > tabIndex) ||
             (childTabIndex < aCurrentTabIndex && childTabIndex > tabIndex)) {
           tabIndex = childTabIndex;
         }
       }
 
       nsAutoString tabIndexStr;

--- a/dom/base/nsIDocument.h
+++ b/dom/base/nsIDocument.h
@@ -3794,21 +3794,16 @@ public:
   void SetAllowPaymentRequest(bool aAllowPaymentRequest)
   {
     mAllowPaymentRequest = aAllowPaymentRequest;
   }
 
   mozilla::dom::FeaturePolicy*
   Policy() const;
 
-  bool IsShadowDOMEnabled() const
-  {
-    return mIsShadowDOMEnabled;
-  }
-
   bool ModuleScriptsEnabled();
 
   /**
    * Find the (non-anonymous) content in this document for aFrame. It will
    * be aFrame's content node if that content is in this document and not
    * anonymous. Otherwise, when aFrame is in a subdocument, we use the frame
    * element containing the subdocument containing aFrame, and/or find the
    * nearest non-anonymous ancestor in this document.
@@ -4266,20 +4261,16 @@ protected:
   bool mDidCallBeginLoad : 1;
 
   // True if the document is allowed to use PaymentRequest.
   bool mAllowPaymentRequest : 1;
 
   // True if the encoding menu should be disabled.
   bool mEncodingMenuDisabled : 1;
 
-  // True if dom.webcomponents.shadowdom.enabled pref is set when document is
-  // created.
-  bool mIsShadowDOMEnabled : 1;
-
   // True if this document is for an SVG-in-OpenType font.
   bool mIsSVGGlyphsDocument : 1;
 
   // True if the document is being destroyed.
   bool mInDestructor: 1;
 
   // True if the document has been detached from its content viewer.
   bool mIsGoingAway: 1;

--- a/dom/base/nsTextNode.cpp
+++ b/dom/base/nsTextNode.cpp
@@ -146,22 +146,16 @@ nsTextNode::BindToTree(nsIDocument* aDoc
 
 void nsTextNode::UnbindFromTree(bool aDeep, bool aNullParent)
 {
   ResetDirectionSetByTextNode(this);
 
   CharacterData::UnbindFromTree(aDeep, aNullParent);
 }
 
-bool
-nsTextNode::IsShadowDOMEnabled(JSContext* aCx, JSObject* aObject)
-{
-  return nsDocument::IsShadowDOMEnabled(aCx, aObject);
-}
-
 #ifdef DEBUG
 void
 nsTextNode::List(FILE* out, int32_t aIndent) const
 {
   int32_t index;
   for (index = aIndent; --index >= 0; ) fputs("  ", out);
 
   fprintf(out, "Text@%p", static_cast<const void*>(this));

--- a/dom/base/nsTextNode.h
+++ b/dom/base/nsTextNode.h
@@ -55,20 +55,16 @@ public:
   virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                               nsIContent* aBindingParent) override;
   virtual void UnbindFromTree(bool aDeep = true,
                               bool aNullParent = true) override;
 
   nsresult AppendTextForNormalize(const char16_t* aBuffer, uint32_t aLength,
                                   bool aNotify, nsIContent* aNextSibling);
 
-  // Need to have a copy here because including nsDocument.h in this file will
-  // fail to build on Windows.
-  static bool IsShadowDOMEnabled(JSContext* aCx, JSObject* aObject);
-
 #ifdef DEBUG
   virtual void List(FILE* out, int32_t aIndent) const override;
   virtual void DumpContent(FILE* out, int32_t aIndent, bool aDumpAll) const override;
 #endif
 
 protected:
   virtual ~nsTextNode();

--- a/dom/base/test/test_bug1025933.html
+++ b/dom/base/test/test_bug1025933.html
@@ -10,35 +10,29 @@ https://bugzilla.mozilla.org/show_bug.cg
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
   /** Test for Bug 1025933 **/
 
   SimpleTest.waitForExplicitFinish();
 
   function test() {
-    SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.webcomponents.shadowdom.enabled", true]
-      ]
-    }, function() {
-      var iframe = document.createElement('iframe');
-      iframe.srcdoc = '<div id="content"> <div id="host"></div </div>';
+    var iframe = document.createElement('iframe');
+    iframe.srcdoc = '<div id="content"> <div id="host"></div </div>';
 
-      iframe.onload = function() {
-        var s = iframe.contentDocument.getElementById("host").attachShadow({mode: 'open'});
-        s.innerHTML = '<div style="width:100px;height:100px;background:red"></div>';
-        var el = s.firstElementChild;
-        is(el.clientWidth, 100);
-        is(el.clientHeight, 100);
-        SimpleTest.finish();
-      }
+    iframe.onload = function() {
+      var s = iframe.contentDocument.getElementById("host").attachShadow({mode: 'open'});
+      s.innerHTML = '<div style="width:100px;height:100px;background:red"></div>';
+      var el = s.firstElementChild;
+      is(el.clientWidth, 100);
+      is(el.clientHeight, 100);
+      SimpleTest.finish();
+    }
 
-      document.body.appendChild(iframe);
-    });
+    document.body.appendChild(iframe);
   }
 
   </script>
 </head>
 <body onload="test()">
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1025933">Mozilla Bug 1025933</a>
 <p id="display"></p>
 <pre id="test">

--- a/dom/base/test/test_bug1037687.html
+++ b/dom/base/test/test_bug1037687.html
@@ -15,22 +15,18 @@ https://bugzilla.mozilla.org/show_bug.cg
 <div id="content" style="display: none">
 
 </div>
 <pre id="test">
 </pre>
 <script type="application/javascript">
   /** Test for Bug 1037687 **/
   SimpleTest.waitForExplicitFinish();
-  SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.webcomponents.shadowdom.enabled", true]
-    ]
-  }, function() {
+  window.onload = function() {
     // This test loads in an iframe, to ensure that the element instance is
     // loaded with the correct value of the preference.
     let iframe = document.createElement("iframe");
     iframe.src = "test_bug1037687_subframe.html";
     document.body.appendChild(iframe);
-  });
+  };
 </script>
 </body>
 </html>

--- a/dom/base/test/test_bug1100912.html
+++ b/dom/base/test/test_bug1100912.html
@@ -8,37 +8,27 @@ https://bugzilla.mozilla.org/show_bug.cg
   <title>Test for Bug 1100912</title>
   <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
   /** Test for Bug 1100912 **/
 
   SimpleTest.waitForExplicitFinish();
 
-  function init() {
-    SpecialPowers.pushPrefEnv(
-      {
-        "set": [["dom.webcomponents.shadowdom.enabled", true]]
-      },
-      runTests);
-  }
-
   function runTests() {
     win = window.open("file_bug1100912.html", "");
   }
 
   function didRunTests() {
     setTimeout("SimpleTest.finish()");
   }
 
-  SimpleTest.waitForFocus(init);
-
   </script>
 </head>
-<body>
+<body onload="SimpleTest.waitForFocus(runTests)">
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1100912">Mozilla Bug 1100912</a>
 <p id="display"></p>
 <div id="content" style="display: none">
 
 </div>
 <pre id="test">
 </pre>
 </body>

--- a/dom/base/test/test_bug1421568.html
+++ b/dom/base/test/test_bug1421568.html
@@ -10,23 +10,18 @@ https://bugzilla.mozilla.org/show_bug.cg
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript"><!--
 
   /** Test for Bug 1421568 **/
 
   SimpleTest.waitForExplicitFinish();
 
   function init() {
-    SpecialPowers.pushPrefEnv({
-      set: [["dom.webcomponents.shadowdom.enabled", true]]
-      },
-      function () {
-        document.getElementById("content").innerHTML =
-          "<iframe src='about:blank' onload='test(this)'></iframe>";
-      });
+    document.getElementById("content").innerHTML =
+      "<iframe src='about:blank' onload='test(this)'></iframe>";
   }
 
   function test(iframe) {
     var d = iframe.contentDocument;
     d.body.innerHTML = "<div>";
     var div = d.body.firstChild;
     var sr = div.attachShadow({mode: "closed"});
     is(sr.mode, "closed", "Shadow root should be closed.");

--- a/dom/base/test/test_bug1453693.html
+++ b/dom/base/test/test_bug1453693.html
@@ -9,32 +9,24 @@ https://bugzilla.mozilla.org/show_bug.cg
   <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
   /** Test for Bug 1453693 **/
 
   SimpleTest.waitForExplicitFinish();
 
-  function init() {
-    SpecialPowers.pushPrefEnv(
-      {
-        "set": [["dom.webcomponents.shadowdom.enabled", true]]
-      },
-      runTests);
-  }
-
   function runTests() {
     win = window.open("file_bug1453693.html", "", "width=300, height=300");
   }
 
   function didRunTests() {
     setTimeout("SimpleTest.finish()");
   }
 
-  SimpleTest.waitForFocus(init);
+  ;
 
   </script>
 </head>
-<body>
+<body onload="SimpleTest.waitForFocus(runTests);">
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1453693">Mozilla Bug 1453693</a>
 </body>
 </html>

--- a/dom/base/test/test_bug1472427.html
+++ b/dom/base/test/test_bug1472427.html
@@ -72,17 +72,17 @@ https://bugzilla.mozilla.org/show_bug.cg
     expectedTarget = img;
     synthesizeMouse(img, 50, 50, {}, ifr.contentWindow);
     ok(gotClick, "Should have got a click event.");
     SimpleTest.finish();
   }
 
   </script>
 </head>
-<body onload="SpecialPowers.pushPrefEnv({'set':[['dom.webcomponents.shadowdom.enabled', true]]}, initPage);">
+<body onload="initPage()">
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1472427">Mozilla Bug 1472427</a>
 <p id="display"></p>
 <div id="content" style="display: none">
 
 </div>
 <pre id="test">
 </pre>
 </body>

--- a/dom/base/test/test_find.html
+++ b/dom/base/test/test_find.html
@@ -108,18 +108,16 @@ let runTests = t.step_func_done(function
   testFindable(true, "Shadow text", function(document) {
     let div = document.createElement("div");
     div.appendChild(document.createTextNode("text, yay!"));
     div.attachShadow({ mode: "open" }).innerHTML = `This is Shadow <slot></slot>`;
     document.documentElement.appendChild(div);
   }, "Mixed shadow and non-shadow text");
 });
 
-SpecialPowers.pushPrefEnv(
-  {"set":[['dom.webcomponents.shadowdom.enabled', true]]},
-  t.step_func(function() {
-    let iframe = document.createElement("iframe");
-    iframe.onload = runTests;
-    iframe.srcdoc = "<!doctype html><html></html>";
-    document.body.appendChild(iframe);
-  }));
+window.onload = function() {
+  let iframe = document.createElement("iframe");
+  iframe.onload = runTests;
+  iframe.srcdoc = "<!doctype html><html></html>";
+  document.body.appendChild(iframe);
+};
 </script>
 </body>

--- a/dom/base/test/test_range_bounds.html
+++ b/dom/base/test/test_range_bounds.html
@@ -113,56 +113,56 @@ function doTest(){
     spanInFirstDivRect = spanInFirstDiv.getBoundingClientRect(),
     secondPRect = secondP.getBoundingClientRect(),
     secondDivRect = secondDiv.getBoundingClientRect(),
     spanInSecondPRect = spanInSecondP.getBoundingClientRect(),
     spanInSecondDivRect = spanInSecondDiv.getBoundingClientRect(),
     spanInSecondDivRectList = spanInSecondDiv.getClientRects();
   var widthPerchar = spanInSecondPRect.width / spanInSecondP.firstChild.length;
   var testcases = [
-    {name:'nodesNotInDocument', range:[document.createTextNode('abc'), 1], 
+    {name:'nodesNotInDocument', range:[document.createTextNode('abc'), 1],
       rect:null},
     {name:'collapsedInBlockNode', range:[firstP, 2], rect:null},
     {name:'collapsedAtBeginningOfTextNode', range:[firstP.firstChild, 0],
-      rect:[spanInFirstPRect.left - 6 * widthPerchar, 
-      spanInFirstPRect.left - 6 * widthPerchar, spanInFirstPRect.top, 
+      rect:[spanInFirstPRect.left - 6 * widthPerchar,
+      spanInFirstPRect.left - 6 * widthPerchar, spanInFirstPRect.top,
       spanInFirstPRect.bottom, 0, spanInFirstPRect.height]},
-    {name:'collapsedWithinTextNode', range:[firstP.firstChild, 1], 
-      rect:[spanInFirstPRect.left  - 5 * widthPerchar, 
+    {name:'collapsedWithinTextNode', range:[firstP.firstChild, 1],
+      rect:[spanInFirstPRect.left  - 5 * widthPerchar,
         spanInFirstPRect.left  - 5 * widthPerchar,
         spanInFirstPRect.top, spanInFirstPRect.bottom, 0, spanInFirstPRect.height]},
-    {name:'collapsedAtEndOfTextNode', range:[firstP.firstChild, 6], 
+    {name:'collapsedAtEndOfTextNode', range:[firstP.firstChild, 6],
       rect:[spanInFirstPRect.left, spanInFirstPRect.left,
         spanInFirstPRect.top, spanInFirstPRect.bottom, 0, spanInFirstPRect.height]},
     {name:'singleBlockNode', range:[root, 1, root, 2], rect:firstPRect},
     {name:'twoBlockNodes', range:[root, 1, root, 3],
       rect:[firstPRect.left, firstPRect.right, firstPRect.top,
         firstDivRect.bottom, firstPRect.width,
         firstDivRect.bottom - firstPRect.top],
       rectList:[firstPRect, firstDivRect]},
     {name:'endOfTextNodeToEndOfAnotherTextNodeInAnotherBlock',
       range:[spanInFirstP.firstChild, 1, firstDiv.firstChild, 5],
       rect:[spanInFirstDivRect.left - 5*widthPerchar, spanInFirstDivRect.left,
-        spanInFirstDivRect.top, spanInFirstDivRect.bottom, 5 * widthPerchar, 
+        spanInFirstDivRect.top, spanInFirstDivRect.bottom, 5 * widthPerchar,
         spanInFirstDivRect.height]},
-    {name:'startOfTextNodeToStartOfAnotherTextNodeInAnotherBlock', 
+    {name:'startOfTextNodeToStartOfAnotherTextNodeInAnotherBlock',
       range:[spanInFirstP.firstChild, 0, firstDiv.firstChild, 0],
       rect:[spanInFirstPRect.left, spanInFirstPRect.left + widthPerchar, spanInFirstPRect.top,
         spanInFirstPRect.bottom, widthPerchar, spanInFirstPRect.height]},
-    {name:'endPortionOfATextNode', range:[firstP.firstChild, 3, 
+    {name:'endPortionOfATextNode', range:[firstP.firstChild, 3,
         firstP.firstChild, 6],
       rect:[spanInFirstPRect.left - 3*widthPerchar, spanInFirstPRect.left,
         spanInFirstPRect.top, spanInFirstPRect.bottom, 3*widthPerchar, spanInFirstPRect.height]},
-    {name:'startPortionOfATextNode', range:[firstP.firstChild, 0, 
+    {name:'startPortionOfATextNode', range:[firstP.firstChild, 0,
         firstP.firstChild, 3],
-      rect:[spanInFirstPRect.left - 6*widthPerchar, 
+      rect:[spanInFirstPRect.left - 6*widthPerchar,
         spanInFirstPRect.left - 3*widthPerchar, spanInFirstPRect.top,
         spanInFirstPRect.bottom, 3 * widthPerchar, spanInFirstPRect.height]},
     {name:'spanTextNodes', range:[secondP.firstChild, 1, secondP.lastChild, 1],
-      rect:[spanInSecondPRect.left - 3*widthPerchar, spanInSecondPRect.right + 
+      rect:[spanInSecondPRect.left - 3*widthPerchar, spanInSecondPRect.right +
         widthPerchar, spanInSecondPRect.top, spanInSecondPRect.bottom,
         spanInSecondPRect.width + 4*widthPerchar, spanInSecondPRect.height],
       rectList:[[spanInSecondPRect.left - 3*widthPerchar, spanInSecondPRect.left,
         spanInSecondPRect.top, spanInSecondPRect.bottom, 3 * widthPerchar,
         spanInSecondPRect.height],
 	spanInSecondPRect,
 	[spanInSecondPRect.right, spanInSecondPRect.right + widthPerchar,
           spanInSecondPRect.top, spanInSecondPRect.bottom, widthPerchar,
@@ -178,22 +178,22 @@ function doTest(){
        rect: spanInSecondDivRect,
        rectList:[[spanInSecondDivRectList[0].left+widthPerchar,
         spanInSecondDivRectList[0].right, spanInSecondDivRectList[0].top,
 	spanInSecondDivRectList[0].bottom, spanInSecondDivRectList[0].width - widthPerchar,
 	spanInSecondDivRectList[0].height],
 	spanInSecondDivRectList[1],
 	[spanInSecondDivRectList[2].left,
 	spanInSecondDivRectList[2].right - 4 * widthPerchar, spanInSecondDivRectList[2].top,
-	spanInSecondDivRectList[2].bottom, 
+	spanInSecondDivRectList[2].bottom,
 	spanInSecondDivRectList[2].width - 4 * widthPerchar,
 	spanInSecondDivRectList[2].height]]},
       {name:'textAcrossLines',range:[thirdDiv.firstChild, 13, thirdDiv.firstChild, 28],
         rect: [spanInSecondDivRectList[1].left, spanInSecondDivRectList[1].right,
-          spanInSecondDivRectList[1].top + secondDivRect.height, 
+          spanInSecondDivRectList[1].top + secondDivRect.height,
           spanInSecondDivRectList[1].bottom + secondDivRect.height,
           spanInSecondDivRectList[1].width, spanInSecondDivRectList[1].height]}
     ];
   } else {
     directionDependentTestcases = [
       {name:'spanAcrossLines',range:[spanInSecondDiv.firstChild, 1, spanInSecondDiv.firstChild, 30],
        rect: spanInSecondDivRect,
        rectList:[[spanInSecondDivRectList[0].left+widthPerchar,
@@ -201,30 +201,30 @@ function doTest(){
 	spanInSecondDivRectList[0].bottom, spanInSecondDivRectList[0].width - widthPerchar,
 	spanInSecondDivRectList[0].height],
 	spanInSecondDivRectList[1],
 	spanInSecondDivRectList[2],
 	spanInSecondDivRectList[3],
 	[spanInSecondDivRectList[4].left,
 	spanInSecondDivRectList[4].right - 4 * widthPerchar,
         spanInSecondDivRectList[4].top,
-	spanInSecondDivRectList[4].bottom, 
+	spanInSecondDivRectList[4].bottom,
 	spanInSecondDivRectList[4].width - 4 * widthPerchar,
 	spanInSecondDivRectList[4].height]]},
       {name:'textAcrossLines',range:[thirdDiv.firstChild, 13, thirdDiv.firstChild, 28],
         rect: [spanInSecondDivRectList[2].left, spanInSecondDivRectList[2].right,
-          spanInSecondDivRectList[2].top + secondDivRect.height, 
+          spanInSecondDivRectList[2].top + secondDivRect.height,
           spanInSecondDivRectList[2].bottom + secondDivRect.height,
 	       spanInSecondDivRectList[2].width, spanInSecondDivRectList[2].height],
        rectList:[[spanInSecondDivRectList[2].left, spanInSecondDivRectList[2].right,
-          spanInSecondDivRectList[2].top + secondDivRect.height, 
+          spanInSecondDivRectList[2].top + secondDivRect.height,
           spanInSecondDivRectList[2].bottom + secondDivRect.height,
           spanInSecondDivRectList[2].width, spanInSecondDivRectList[2].height],
           [spanInSecondDivRectList[2].left, spanInSecondDivRectList[2].left,
-          spanInSecondDivRectList[2].top + secondDivRect.height, 
+          spanInSecondDivRectList[2].top + secondDivRect.height,
           spanInSecondDivRectList[2].bottom + secondDivRect.height,
           0, spanInSecondDivRectList[2].height]]}
      ];
   }
   directionDependentTestcases.forEach(runATest);
 }
 function testMixedDir(){
   var root = document.getElementById('mixeddir');
@@ -234,17 +234,17 @@ function testMixedDir(){
              rect: firstSpanRect, rectList:firstSpanRectList});
 
   root = document.getElementById('mixeddir2');
   firstSpan = root.firstElementChild;
   firstSpanRect = firstSpan.getBoundingClientRect();
   bdo = document.getElementById('bdo2');
   bdoRect=bdo.getBoundingClientRect();
   var widthPerChar = bdoRect.width / bdo.firstChild.length;
-  runATest({name:'mixeddirPartial', range:[firstSpan.firstChild, 3, 
+  runATest({name:'mixeddirPartial', range:[firstSpan.firstChild, 3,
 					   bdo.firstChild, 7],
 	rect: [firstSpanRect.left + 3*widthPerChar, bdoRect.right,
 	       bdoRect.top, bdoRect.bottom,
 	       (firstSpan.firstChild.length + bdo.firstChild.length - 3) *
 	        widthPerChar,
 	       bdoRect.height],
 	rectList:[[firstSpanRect.left + 3*widthPerChar,
 		   bdoRect.left,
@@ -285,21 +285,18 @@ function test(){
 
   testMixedDir();
 
   //test transforms
   isTransformed = true;
   root.style.transform = "translate(30px,50px)";
   doTest();
 
-  SpecialPowers.pushPrefEnv({"set":[["dom.webcomponents.shadowdom.enabled", true]]},
-                            () => {
-                              testShadowDOM();
-                              SimpleTest.finish();
-                            });
+  testShadowDOM();
+  SimpleTest.finish();
 }
 
 window.onload = function() {
   SimpleTest.waitForExplicitFinish();
   setTimeout(test, 0);
 };
 
 </script>

--- a/dom/events/test/test_bug1079236.html
+++ b/dom/events/test/test_bug1079236.html
@@ -43,23 +43,19 @@ https://bugzilla.mozilla.org/show_bug.cg
     }
 
     var r = file.getBoundingClientRect();
     synthesizeMouse(file, r.width / 6, r.height / 2, { type: "mousemove"}, iframe.contentWindow);
     iframe.contentDocument.body.onmousemove = null;
   }
 
   SimpleTest.waitForExplicitFinish();
-  SimpleTest.waitForFocus(() => {
-    SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.webcomponents.shadowdom.enabled", true]
-      ]
-    }, runTests);
-  });
+  window.onload = () => {
+    SimpleTest.waitForFocus(runTests);
+  };
 
   </script>
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1079236">Mozilla Bug 1079236</a>
 <p id="display"></p>
 <div id="content">

--- a/dom/events/test/test_bug1145910.html
+++ b/dom/events/test/test_bug1145910.html
@@ -40,19 +40,15 @@ function runTests() {
 
   is(iframeWin.getComputedStyle(inner).color, "rgb(0, 0, 0)", "Div inside shadow root should no longer be active.");
   is(iframeWin.getComputedStyle(host).color, "rgb(0, 0, 0)", "Host should no longer be active.");
 
   SimpleTest.finish();
 };
 
 SimpleTest.waitForExplicitFinish();
-SimpleTest.waitForFocus(() => {
-  SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.webcomponents.shadowdom.enabled", true]
-    ]
-  }, runTests);
-});
+window.onload = () => {
+  SimpleTest.waitForFocus(runTests);
+};
 
 </script>
 </body>
 </html>

--- a/dom/events/test/test_bug1150308.html
+++ b/dom/events/test/test_bug1150308.html
@@ -36,18 +36,14 @@ function runTests() {
   synthesizeMouseAtCenter(distributed, { type: "mouseup" }, iframeWin);
 
   is(iframeWin.getComputedStyle(inner).color, "rgb(0, 0, 0)", "Div inside shadow root should no longer be active.");
 
   SimpleTest.finish();
 };
 
 SimpleTest.waitForExplicitFinish();
-SimpleTest.waitForFocus(() => {
-  SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.webcomponents.shadowdom.enabled", true]
-    ]
-  }, runTests);
-});
+window.onload = () => {
+  SimpleTest.waitForFocus(runTests);
+};
 </script>
 </body>
 </html>

--- a/dom/events/test/test_bug1264380.html
+++ b/dom/events/test/test_bug1264380.html
@@ -44,21 +44,17 @@ function runTests()
   ok(dragService.getCurrentSession(), "Drag session is available.");
   dragService.endDragSession(false);
   ok(!dragService.getCurrentSession(), "There shouldn't be a drag session anymore!");
   SimpleTest.finish();
 }
 
 
 SimpleTest.waitForExplicitFinish();
-SimpleTest.waitForFocus(() => {
-  SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.webcomponents.shadowdom.enabled", true]
-    ]
-  }, runTests);
-});
+window.onload = () => {
+  SimpleTest.waitForFocus(runTests);
+};
 
 </script>
 
 <body>
 </body>
 </html>

--- a/dom/events/test/test_bug1429572.html
+++ b/dom/events/test/test_bug1429572.html
@@ -10,18 +10,17 @@ https://bugzilla.mozilla.org/show_bug.cg
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
   /** Test for Bug 1429572 **/
   SimpleTest.waitForExplicitFinish();
 
   var win;
   function start() {
-    SpecialPowers.pushPrefEnv({"set": [["dom.webcomponents.shadowdom.enabled", true],
-                                       ["dom.w3c_touch_events.enabled", 1]]},
+    SpecialPowers.pushPrefEnv({"set": [["dom.w3c_touch_events.enabled", 1]]},
     function() {
       ok(true, "Starting the test.");
       win = window.open("window_bug1429572.html", "testwindow",
                         "width=" + window.screen.width +
                         ",height=" + window.screen.height);
     });
   }

--- a/dom/events/test/test_bug1446834.html
+++ b/dom/events/test/test_bug1446834.html
@@ -10,20 +10,17 @@ https://bugzilla.mozilla.org/show_bug.cg
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
   /** Test for Bug 1446834 **/
 
   SimpleTest.waitForExplicitFinish();
 
   window.onload = function() {
-    SpecialPowers.pushPrefEnv({"set": [["dom.webcomponents.shadowdom.enabled", true]]},
-      function() {
-        document.getElementById("iframe").src = "file_bug1446834.html";
-      });
+    document.getElementById("iframe").src = "file_bug1446834.html";
   }
 
   </script>
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1446834">Mozilla Bug 1446834</a>
 <p id="display"></p>
 <div id="content" style="display: none">

--- a/dom/events/test/test_bug1484371.html
+++ b/dom/events/test/test_bug1484371.html
@@ -10,20 +10,17 @@ https://bugzilla.mozilla.org/show_bug.cg
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
   /** Test for Bug 1484371 **/
 
   SimpleTest.waitForExplicitFinish();
 
   window.onload = function() {
-    SpecialPowers.pushPrefEnv({"set": [["dom.webcomponents.shadowdom.enabled", true]]},
-      function() {
-        document.getElementById("iframe").src = "file_bug1484371.html";
-      });
+    document.getElementById("iframe").src = "file_bug1484371.html";
   }
 
   </script>
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1484371">Mozilla Bug 1484371</a>
 <iframe id="iframe"></iframe>
 </body>

--- a/dom/events/test/test_slotted_mouse_event.html
+++ b/dom/events/test/test_slotted_mouse_event.html
@@ -50,16 +50,12 @@ function frameLoaded(iframe) {
     }, 0);
   });
 
   synthesizeMouseAtCenter(host, { type: "mousemove" });
   synthesizeMouseAtCenter(target, { type: "mousemove" });
 }
 
 SimpleTest.waitForExplicitFinish();
-SimpleTest.waitForFocus(() => {
-  SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.webcomponents.shadowdom.enabled", true]
-    ]
-  }, runTests);
-});
+window.onload = () => {
+  SimpleTest.waitForFocus(runTests);
+};
 </script>

--- a/dom/events/test/test_slotted_text_click.html
+++ b/dom/events/test/test_slotted_text_click.html
@@ -61,16 +61,12 @@ function frameLoaded(iframe) {
     requestAnimationFrame(() => {
       synthesizeMouseAtPoint(150, 150, { type: "mousedown" });
       synthesizeMouseAtPoint(150, 150, { type: "mouseup" });
     });
   });
 }
 
 SimpleTest.waitForExplicitFinish();
-SimpleTest.waitForFocus(() => {
-  SpecialPowers.pushPrefEnv({
-    set: [
-      ["dom.webcomponents.shadowdom.enabled", true]
-    ]
-  }, runTests);
-});
+window.onload = () => {
+  SimpleTest.waitForFocus(runTests);
+};
 </script>

--- a/dom/html/HTMLSlotElement.cpp
+++ b/dom/html/HTMLSlotElement.cpp
@@ -12,21 +12,17 @@
 #include "nsGkAtoms.h"
 #include "nsDocument.h"
 
 nsGenericHTMLElement*
 NS_NewHTMLSlotElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
                       mozilla::dom::FromParser aFromParser)
 {
   RefPtr<mozilla::dom::NodeInfo> nodeInfo(std::move(aNodeInfo));
-  if (nsDocument::IsShadowDOMEnabled(nodeInfo->GetDocument())) {
-    return new mozilla::dom::HTMLSlotElement(nodeInfo.forget());
-  }
-
-  return new mozilla::dom::HTMLUnknownElement(nodeInfo.forget());
+  return new mozilla::dom::HTMLSlotElement(nodeInfo.forget());
 }
 
 namespace mozilla {
 namespace dom {
 
 HTMLSlotElement::HTMLSlotElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
   : nsGenericHTMLElement(std::move(aNodeInfo))
 {

--- a/dom/html/test/test_bug1472426.html
+++ b/dom/html/test/test_bug1472426.html
@@ -94,20 +94,17 @@ https://bugzilla.mozilla.org/show_bug.cg
        { name: "textarea", value: "textareavalue" }
       ];
     checkMPSubmission(submission, expected, "form submission inside shadow DOM");
     SimpleTest.finish();
   }
 
   window.onload = function() {
     SimpleTest.waitForExplicitFinish();
-    SpecialPowers.pushPrefEnv({"set":[["dom.webcomponents.shadowdom.enabled", true]]},
-                              () => {
-                                testFormSubmissionInShadowDOM();
-                              });
+    testFormSubmissionInShadowDOM();
   }
 
   </script>
   <template id="template">
     <form action="form_submit_server.sjs" target="target_iframe" id="form"
           method="POST" enctype="multipart/form-data">
       <input name="text" value="textvalue">
       <input name="hidden" value="hiddenvalue" type="hidden">

--- a/dom/html/test/test_fullscreen-api.html
+++ b/dom/html/test/test_fullscreen-api.html
@@ -169,17 +169,16 @@ is(window.fullScreen, false, "Shouldn't 
 // to write
 addLoadEvent(function() {
   SpecialPowers.pushPrefEnv({
       "set": [
         ["full-screen-api.enabled", true],
         ["full-screen-api.unprefix.enabled", true],
         ["full-screen-api.allow-trusted-requests-only", false],
         ["full-screen-api.transition-duration.enter", "0 0"],
-        ["full-screen-api.transition-duration.leave", "0 0"],
-        ["dom.webcomponents.shadowdom.enabled", true]
+        ["full-screen-api.transition-duration.leave", "0 0"]
       ]}, nextTest);
 });
 SimpleTest.waitForExplicitFinish();
 </script>
 </pre>
 </body>
 </html>

--- a/dom/tests/mochitest/pointerlock/test_pointerlock-api.html
+++ b/dom/tests/mochitest/pointerlock/test_pointerlock-api.html
@@ -28,18 +28,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 
         SimpleTest.waitForExplicitFinish();
 
         SpecialPowers.pushPrefEnv({"set": [
           ["full-screen-api.enabled", true],
           ["full-screen-api.unprefix.enabled", true],
           ["full-screen-api.allow-trusted-requests-only", false],
           ["full-screen-api.transition-duration.enter", "0 0"],
-          ["full-screen-api.transition-duration.leave", "0 0"],
-          ["dom.webcomponents.shadowdom.enabled", true]
+          ["full-screen-api.transition-duration.leave", "0 0"]
         ]}, nextTest);
 
         // Run the tests which go full-screen in new window, as Mochitests
         // normally run in an iframe, which by default will not have the
         // allowfullscreen attribute set, so full-screen won't work.
         var gTestFiles = [
           "file_screenClientXYConst.html",
           "file_childIframe.html",

--- a/dom/tests/mochitest/webcomponents/head.js
+++ b/dom/tests/mochitest/webcomponents/head.js
@@ -1,30 +1,22 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 /**
- * Set dom.webcomponents.shadowdom.enabled pref to true and loads an iframe, to
- * ensure that the Element instance is loaded with the correct value of the
- * preference.
+ * Loads an iframe.
  *
  * @return {Promise} promise that resolves when iframe is loaded.
  */
-function setShadowDOMPrefAndCreateIframe(aSrcDoc) {
+function createIframe(aSrcDoc) {
   return new Promise(function (aResolve, aReject) {
-    SpecialPowers.pushPrefEnv({
-      set: [
-        ["dom.webcomponents.shadowdom.enabled", true]
-      ]
-    }, () => {
-      let iframe = document.createElement("iframe");
-      iframe.onload = function () { aResolve(iframe.contentDocument); }
-      iframe.onerror = function () { aReject('Failed to load iframe'); }
-      if (aSrcDoc) {
-        iframe.srcdoc = aSrcDoc;
-      }
-      document.body.appendChild(iframe);
-    });
+    let iframe = document.createElement("iframe");
+    iframe.onload = function () { aResolve(iframe.contentDocument); }
+    iframe.onerror = function () { aReject('Failed to load iframe'); }
+    if (aSrcDoc) {
+      iframe.srcdoc = aSrcDoc;
+    }
+    document.body.appendChild(iframe);
   });
 }

--- a/dom/tests/mochitest/webcomponents/test_bug1269155.html
+++ b/dom/tests/mochitest/webcomponents/test_bug1269155.html
@@ -17,17 +17,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
 /** Test for Bug 1269155 **/
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="content" style="display: none"> </div>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
     var host = aDocument.querySelector('#content');
     var root = host.attachShadow({mode: "open"});
 
     var header1 = aDocument.createElement('h1');
     header1.textContent = 'Shadow Header1';
 
     var paragraph1 = aDocument.createElement('p');

--- a/dom/tests/mochitest/webcomponents/test_custom_element_in_shadow.html
+++ b/dom/tests/mochitest/webcomponents/test_custom_element_in_shadow.html
@@ -12,17 +12,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1087460">Bug 1087460</a>
 
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="container"></div>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
 
     // Test callback for custom element when used after registration.
 
     var iframeWin = aDocument.defaultView;
     var connectedCallbackCount = 0;
     var disconnectedCallbackCount = 0;
     var attributeChangedCallbackCount = 0;

--- a/dom/tests/mochitest/webcomponents/test_detached_style.html
+++ b/dom/tests/mochitest/webcomponents/test_detached_style.html
@@ -11,17 +11,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1062578">Bug 1062578</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="grabme"></div>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
     var host = aDocument.createElement("div");
     var shadow = host.attachShadow({mode: "open"});
     shadow.innerHTML = '<style> #inner { height: 200px; } </style><div id="inner">Hello</div>';
 
     var iframeWin = aDocument.defaultView;
     iframeWin.grabme.appendChild(host);

--- a/dom/tests/mochitest/webcomponents/test_document_adoptnode.html
+++ b/dom/tests/mochitest/webcomponents/test_document_adoptnode.html
@@ -15,17 +15,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <p id="display"></p>
 <div id="content" style="display: none">
 
 </div>
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
 SimpleTest.waitForExplicitFinish();
-setShadowDOMPrefAndCreateIframe()
+createIframe()
   .then((aDocument) => {
     var thrownException = false;
     var shadowRoot = aDocument.createElement('div').attachShadow({mode: "open"});
 
     try {
       aDocument.adoptNode(shadowRoot);
     } catch(err) {
       thrownException = err;

--- a/dom/tests/mochitest/webcomponents/test_document_importnode.html
+++ b/dom/tests/mochitest/webcomponents/test_document_importnode.html
@@ -15,17 +15,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <p id="display"></p>
 <div id="content" style="display: none">
 
 </div>
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
 SimpleTest.waitForExplicitFinish();
-setShadowDOMPrefAndCreateIframe()
+createIframe()
   .then((aDocument) => {
     var thrownException = false;
     var shadowRoot = aDocument.createElement('div').attachShadow({mode: "open"});
 
     try {
       aDocument.importNode(shadowRoot);
     } catch(err) {
       thrownException = err;

--- a/dom/tests/mochitest/webcomponents/test_event_retarget.html
+++ b/dom/tests/mochitest/webcomponents/test_event_retarget.html
@@ -9,17 +9,17 @@ https://bugzilla.mozilla.org/show_bug.cg
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=887541">Bug 887541</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
-setShadowDOMPrefAndCreateIframe()
+createIframe()
   .then((aDocument) => {
     /*
      * Creates an event listener with an expected event target.
      */
     function createEventListener(expectedTarget, msg) {
       return function(e) {
         is(e.target, expectedTarget, msg);
       };

--- a/dom/tests/mochitest/webcomponents/test_event_stopping.html
+++ b/dom/tests/mochitest/webcomponents/test_event_stopping.html
@@ -12,17 +12,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=887541">Bug 887541</a>
 <script>
 
 var els = SpecialPowers.Cc["@mozilla.org/eventlistenerservice;1"]
             .getService(SpecialPowers.Ci.nsIEventListenerService);
 
 SimpleTest.waitForExplicitFinish();
-setShadowDOMPrefAndCreateIframe()
+createIframe()
   .then((aDocument) => {
     function eventListener(e) {
       eventChain.push(this);
     }
 
     function isEventChain(actual, expected, msg) {
       is(actual.length, expected.length, msg);
       for (var i = 0; i < expected.length; i++) {

--- a/dom/tests/mochitest/webcomponents/test_shadowroot.html
+++ b/dom/tests/mochitest/webcomponents/test_shadowroot.html
@@ -12,17 +12,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=806506">Bug 806506</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="movedtoshadow" class="testclass"></div>' +
               '<svg id="svgmovedtoshadow"></svg>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
     // Create ShadowRoot.
     var element = aDocument.createElement("div");
     ok(!element.shadowRoot, "div element should not have a shadow root.");
     var shadow = element.attachShadow({mode: "open"});
     is(element.shadowRoot, shadow, "shadowRoot property should return the same shadow root that was just created.");
 
     // Move an element from the document to the ShadowRoot.

--- a/dom/tests/mochitest/webcomponents/test_shadowroot_clonenode.html
+++ b/dom/tests/mochitest/webcomponents/test_shadowroot_clonenode.html
@@ -17,17 +17,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <div id="content" style="display: none">
 
 </div>
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
 /** Test for Bug 1429982 **/
 SimpleTest.waitForExplicitFinish();
-setShadowDOMPrefAndCreateIframe()
+createIframe()
   .then((aDocument) => {
     var element = aDocument.createElement("div");
     var shadowRoot = element.attachShadow({mode: "open"});
     var thrownException = false;
 
     try {
       shadowRoot.cloneNode();
     } catch(err) {

--- a/dom/tests/mochitest/webcomponents/test_shadowroot_inert_element.html
+++ b/dom/tests/mochitest/webcomponents/test_shadowroot_inert_element.html
@@ -11,17 +11,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=806506">Bug 806506</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="grabme"></div>';
-setShadowDOMPrefAndCreateIframe(content).then(aDocument => {
+createIframe(content).then(aDocument => {
   var element = aDocument.getElementById("grabme");
   var shadow = element.attachShadow({mode: "open"});
 
   // Check that <base> is inert.
   shadow.innerHTML = '<base href="http://www.example.org/" />';
   isnot(aDocument.baseURI, "http://www.example.org/", "Base element should be inert in ShadowRoot.");
   SimpleTest.finish();
 });

--- a/dom/tests/mochitest/webcomponents/test_shadowroot_style.html
+++ b/dom/tests/mochitest/webcomponents/test_shadowroot_style.html
@@ -12,17 +12,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=806506">Bug 806506</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div class="tall" id="bodydiv"></div>' +
               '<div id="container"></div>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
     var iframeWin = aDocument.defaultView;
 
     // Create ShadowRoot.
     var container = aDocument.getElementById("container");
     var elem = aDocument.createElement("div");
     container.appendChild(elem); // Put ShadowRoot host in document.
     var root = elem.attachShadow({mode: "open"});

--- a/dom/tests/mochitest/webcomponents/test_shadowroot_style_order.html
+++ b/dom/tests/mochitest/webcomponents/test_shadowroot_style_order.html
@@ -11,17 +11,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=806506">Bug 806506</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="container"></div>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
     var iframeWin = aDocument.defaultView;
 
     // Create ShadowRoot.
     var container = aDocument.getElementById("container");
     var elem = aDocument.createElement("div");
     container.appendChild(elem); // Put ShadowRoot host in document.
     var root = elem.attachShadow({mode: "open"});

--- a/dom/tests/mochitest/webcomponents/test_style_fallback_content.html
+++ b/dom/tests/mochitest/webcomponents/test_style_fallback_content.html
@@ -11,17 +11,17 @@ https://bugzilla.mozilla.org/show_bug.cg
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=806506">Bug 806506</a>
 <script>
 
 SimpleTest.waitForExplicitFinish();
 
 var content = '<div id="grabme"></div>';
-setShadowDOMPrefAndCreateIframe(content)
+createIframe(content)
   .then((aDocument) => {
     var iframeWin = aDocument.defaultView;
 
     var host = aDocument.getElementById("grabme");
     var shadow = host.attachShadow({mode: "open"});
     shadow.innerHTML = '<style id="innerstyle"></style><span id="container"><slot><span id="innerspan">Hello</span></slot></span>';
     var innerStyle = shadow.getElementById("innerstyle");

--- a/dom/webidl/Element.webidl
+++ b/dom/webidl/Element.webidl
@@ -230,31 +230,31 @@ partial interface Element {
 // https://dom.spec.whatwg.org/#dictdef-shadowrootinit
 dictionary ShadowRootInit {
   required ShadowRootMode mode;
 };
 
 // https://dom.spec.whatwg.org/#element
 partial interface Element {
   // Shadow DOM v1
-  [Throws, Func="nsDocument::IsShadowDOMEnabled"]
+  [Throws]
   ShadowRoot attachShadow(ShadowRootInit shadowRootInitDict);
-  [BinaryName="shadowRootByMode", Func="nsDocument::IsShadowDOMEnabled"]
+  [BinaryName="shadowRootByMode"]
   readonly attribute ShadowRoot? shadowRoot;
 
-  [Func="nsDocument::IsShadowDOMEnabledAndCallerIsChromeOrAddon", BinaryName="shadowRoot"]
+  [Func="nsDocument::IsCallerChromeOrAddon", BinaryName="shadowRoot"]
   readonly attribute ShadowRoot? openOrClosedShadowRoot;
 
-  [BinaryName="assignedSlotByMode", Func="nsDocument::IsShadowDOMEnabled"]
+  [BinaryName="assignedSlotByMode"]
   readonly attribute HTMLSlotElement? assignedSlot;
 
-  [ChromeOnly, BinaryName="assignedSlot", Func="nsDocument::IsShadowDOMEnabled"]
+  [ChromeOnly, BinaryName="assignedSlot"]
   readonly attribute HTMLSlotElement? openOrClosedAssignedSlot;
 
-  [CEReactions, Unscopable, SetterThrows, Func="nsDocument::IsShadowDOMEnabled"]
+  [CEReactions, Unscopable, SetterThrows]
            attribute DOMString slot;
 };
 
 Element implements ChildNode;
 Element implements NonDocumentTypeChildNode;
 Element implements ParentNode;
 Element implements Animatable;
 Element implements GeometryUtils;

--- a/dom/webidl/HTMLSlotElement.webidl
+++ b/dom/webidl/HTMLSlotElement.webidl
@@ -6,17 +6,17 @@
  * The origin of this IDL file is
  * https://html.spec.whatwg.org/multipage/forms.html#the-dialog-element
  *
  * © Copyright 2004-2011 Apple Computer, Inc., Mozilla Foundation, and
  * Opera Software ASA. You are granted a license to use, reproduce
  * and create derivative works of this document.
  */
 
-[Func="nsDocument::IsShadowDOMEnabled", Exposed=Window, HTMLConstructor]
+[Exposed=Window, HTMLConstructor]
 interface HTMLSlotElement : HTMLElement {
   [CEReactions, SetterThrows] attribute DOMString name;
   sequence<Node> assignedNodes(optional AssignedNodesOptions options);
 };
 
 dictionary AssignedNodesOptions {
   boolean flatten = false;
 };

--- a/dom/webidl/ShadowRoot.webidl
+++ b/dom/webidl/ShadowRoot.webidl
@@ -12,17 +12,16 @@
 
 // https://dom.spec.whatwg.org/#enumdef-shadowrootmode
 enum ShadowRootMode {
   "open",
   "closed"
 };
 
 // https://dom.spec.whatwg.org/#shadowroot
-[Func="nsDocument::IsShadowDOMEnabled"]
 interface ShadowRoot : DocumentFragment
 {
   // Shadow DOM v1
   readonly attribute ShadowRootMode mode;
   readonly attribute Element host;
 
   // [deprecated] Shadow DOM v0
   Element? getElementById(DOMString elementId);

--- a/dom/webidl/Text.webidl
+++ b/dom/webidl/Text.webidl
@@ -14,16 +14,16 @@
 interface Text : CharacterData {
   [Throws]
   Text splitText(unsigned long offset);
   [Throws]
   readonly attribute DOMString wholeText;
 };
 
 partial interface Text {
-  [BinaryName="assignedSlotByMode", Func="nsTextNode::IsShadowDOMEnabled"]
+  [BinaryName="assignedSlotByMode"]
   readonly attribute HTMLSlotElement? assignedSlot;
 
-  [ChromeOnly, BinaryName="assignedSlot", Func="nsTextNode::IsShadowDOMEnabled"]
+  [ChromeOnly, BinaryName="assignedSlot"]
   readonly attribute HTMLSlotElement? openOrClosedAssignedSlot;
 };
 
 Text implements GeometryUtils;

--- a/dom/xml/nsXMLPrettyPrinter.cpp
+++ b/dom/xml/nsXMLPrettyPrinter.cpp
@@ -7,18 +7,16 @@
 #include "nsContentUtils.h"
 #include "nsICSSDeclaration.h"
 #include "nsIObserver.h"
 #include "nsSyncLoadService.h"
 #include "nsPIDOMWindow.h"
 #include "nsIServiceManager.h"
 #include "nsNetUtil.h"
 #include "mozilla/dom/Element.h"
-#include "nsBindingManager.h"
-#include "nsXBLService.h"
 #include "nsIScriptSecurityManager.h"
 #include "mozilla/Preferences.h"
 #include "nsIDocument.h"
 #include "nsVariant.h"
 #include "mozilla/dom/CustomEvent.h"
 #include "mozilla/dom/DocumentFragment.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/ToJSValue.h"
@@ -123,104 +121,41 @@ nsXMLPrettyPrinter::PrettyPrint(nsIDocum
     if (NS_WARN_IF(err.Failed())) {
         return err.StealNSResult();
     }
 
     // Find the root element
     RefPtr<Element> rootElement = aDocument->GetRootElement();
     NS_ENSURE_TRUE(rootElement, NS_ERROR_UNEXPECTED);
 
-    if (nsContentUtils::IsShadowDOMEnabled()) {
-        // Attach a closed shadow root on it.
-        RefPtr<ShadowRoot> shadowRoot =
-            rootElement->AttachShadowWithoutNameChecks(ShadowRootMode::Closed);
-
-        // Append the document fragment to the shadow dom.
-        shadowRoot->AppendChild(*resultFragment, err);
-        if (NS_WARN_IF(err.Failed())) {
-            return err.StealNSResult();
-        }
-    } else {
-        //
-        // Apply the prettprint XBL binding.
-        //
-        // We take some shortcuts here. In particular, we don't bother invoking the
-        // contstructor (since the binding has no constructor), and we don't bother
-        // calling LoadBindingDocument because it's a chrome:// URI and thus will get
-        // sync loaded no matter what.
-        //
-
-        // Grab the XBL service.
-        nsXBLService* xblService = nsXBLService::GetInstance();
-        NS_ENSURE_TRUE(xblService, NS_ERROR_NOT_AVAILABLE);
-
-        // Compute the binding URI.
-        nsCOMPtr<nsIURI> bindingUri;
-        rv = NS_NewURI(getter_AddRefs(bindingUri),
-            NS_LITERAL_STRING("chrome://global/content/xml/XMLPrettyPrint.xml#prettyprint"));
-        NS_ENSURE_SUCCESS(rv, rv);
-
-        // Grab the system principal.
-        nsCOMPtr<nsIPrincipal> sysPrincipal;
-        nsContentUtils::GetSecurityManager()->
-            GetSystemPrincipal(getter_AddRefs(sysPrincipal));
+    // Attach a closed shadow root on it.
+    RefPtr<ShadowRoot> shadowRoot =
+        rootElement->AttachShadowWithoutNameChecks(ShadowRootMode::Closed);
 
-        // Destroy any existing frames before we unbind anonymous content.
-        // Note that the shell might be Destroy'ed by now (see bug 1415541).
-        if (!shell->IsDestroying()) {
-            shell->DestroyFramesForAndRestyle(rootElement);
-        }
-
-        // Load the bindings.
-        RefPtr<nsXBLBinding> unused;
-        bool ignored;
-        rv = xblService->LoadBindings(rootElement, bindingUri, sysPrincipal,
-                                      getter_AddRefs(unused), &ignored);
-        NS_ENSURE_SUCCESS(rv, rv);
-
-        // Fire an event at the bound element to pass it |resultFragment|.
-        RefPtr<CustomEvent> event =
-          NS_NewDOMCustomEvent(rootElement, nullptr, nullptr);
-        MOZ_ASSERT(event);
-        AutoJSAPI jsapi;
-        if (!jsapi.Init(event->GetParentObject())) {
-            return NS_ERROR_UNEXPECTED;
-        }
-        JSContext* cx = jsapi.cx();
-        JS::Rooted<JS::Value> detail(cx);
-        if (!ToJSValue(cx, resultFragment, &detail)) {
-            return NS_ERROR_UNEXPECTED;
-        }
-        event->InitCustomEvent(cx, NS_LITERAL_STRING("prettyprint-dom-created"),
-                               /* bubbles = */ false, /* cancelable = */ false,
-                               detail);
-
-        event->SetTrusted(true);
-        rootElement->DispatchEvent(*event, err);
-        if (NS_WARN_IF(err.Failed())) {
-            return err.StealNSResult();
-        }
+    // Append the document fragment to the shadow dom.
+    shadowRoot->AppendChild(*resultFragment, err);
+    if (NS_WARN_IF(err.Failed())) {
+        return err.StealNSResult();
     }
 
     // Observe the document so we know when to switch to "normal" view
     aDocument->AddObserver(this);
     mDocument = aDocument;
 
     NS_ADDREF_THIS();
 
     return NS_OK;
 }
 
 void
 nsXMLPrettyPrinter::MaybeUnhook(nsIContent* aContent)
 {
     // If aContent is null, the document-node was modified.
-    // If it is not null but in the shadow tree, the <scrollbar> NACs,
-    // or the XBL binding, the change was in the generated content, and
-    // it should be ignored.
+    // If it is not null but in the shadow tree or the <scrollbar> NACs,
+    // the change was in the generated content, and it should be ignored.
     bool isGeneratedContent = !aContent ?
         false :
         aContent->GetBindingParent() || aContent->IsInShadowTree();
 
     if (!isGeneratedContent && !mUnhookPending) {
         // Can't blindly to mUnhookPending after AddScriptRunner,
         // since AddScriptRunner _could_ in theory run us
         // synchronously
@@ -234,19 +169,16 @@ void
 nsXMLPrettyPrinter::Unhook()
 {
     mDocument->RemoveObserver(this);
     nsCOMPtr<Element> element = mDocument->GetDocumentElement();
 
     if (element) {
         // Remove the shadow root
         element->UnattachShadow();
-
-        // Remove the bound XBL binding
-        mDocument->BindingManager()->ClearBinding(element);
     }
 
     mDocument = nullptr;
 
     NS_RELEASE_THIS();
 }
 
 void

deleted file mode 100644
--- a/dom/xml/resources/XMLPrettyPrint.xml
+++ /dev/null
@@ -1,30 +0,0 @@
-<?xml version="1.0"?>
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<bindings xmlns="http://www.mozilla.org/xbl"
-          xmlns:html="http://www.w3.org/1999/xhtml">
-
-  <binding id="prettyprint" bindToUntrustedContent="true">
-
-    <content><html:div id="top"/>
-      <html:span style="display: none;"><children/></html:span>
-    </content>
-
-    <handlers>
-      <handler event="prettyprint-dom-created" allowuntrusted="false">
-        <![CDATA[
-          let container = document.getAnonymousNodes(this).item(0);
-          // Take the child nodes from the passed <div id="top">
-          // and append them to our own.
-          for (let el of event.detail.childNodes) {
-            container.appendChild(el);
-          }
-        ]]>
-      </handler>
-    </handlers>
-
-  </binding>
-
-</bindings>

--- a/dom/xml/resources/jar.mn
+++ b/dom/xml/resources/jar.mn
@@ -1,8 +1,7 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 toolkit.jar:
     content/global/xml/XMLPrettyPrint.css                 (XMLPrettyPrint.css)
     content/global/xml/XMLPrettyPrint.xsl                 (XMLPrettyPrint.xsl)
-    content/global/xml/XMLPrettyPrint.xml                 (XMLPrettyPrint.xml)

--- a/layout/base/crashtests/crashtests.list
+++ b/layout/base/crashtests/crashtests.list
@@ -462,17 +462,17 @@ load 1127198-1.html
 load 1140198.html
 load 1143535.html
 load 1153716.html
 load 1156588.html
 load 1162813.xul
 load 1163583.html
 load 1234622-1.html
 load 1235467-1.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1261351.html
+load 1261351.html
 load 1270797-1.html
 load 1278455-1.html
 load 1286889.html
 load 1288608.html
 load 1288946-1.html
 load 1288946-2a.html
 load 1288946-2b.html
 load 1297835.html
@@ -502,44 +502,44 @@ load 1400438-1.html
 load 1400599-1.html
 load 1401739.html
 load 1401840.html
 load 1402476.html
 load 1404789-2.html
 load 1406562.html
 load 1409147.html
 load 1411138.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1414100.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1414303.html
+load 1414100.html
+load 1414303.html
 load 1419762.html
 load 1419802.html
 load 1420533.html
 load 1423216.html
 load 1425893.html
 load 1425959.html
 load 1428353.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1429088.html
+load 1429088.html
 load 1429961.html
 load 1429962.html
 load 1435015.html
 load 1437155.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1439016.html
+load 1439016.html
 load 1442506.html
 load 1443027-1.html
 load 1448841-1.html
 load 1452839.html
 load 1453196.html
 load 1453342.html
 load 1453702.html
 load 1458121.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1461749.html
+load 1461749.html
 load 1461812.html
 load 1462412.html
 load 1463940.html
-pref(dom.webcomponents.shadowdom.enabled,true) HTTP load 1464641.html
+HTTP load 1464641.html
 load 1464737.html
 load 1466638.html
 load 1467688.html
 load 1467964.html
 load 1469354.html
 pref(layout.accessiblecaret.enabled,true) load 1472020.html
 load 1472027.html
 load 1477847.html

--- a/layout/base/tests/chrome/test_printpreview.xul
+++ b/layout/base/tests/chrome/test_printpreview.xul
@@ -6,13 +6,11 @@
   <script type="application/javascript"
           src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
 <body xmlns="http://www.w3.org/1999/xhtml">
 </body>
   <!-- test code goes here -->
 <script type="application/javascript">
 <![CDATA[
 SimpleTest.waitForExplicitFinish();
-SpecialPowers.pushPrefEnv({"set":[["dom.webcomponents.shadowdom.enabled", true]]}, function() {
-  window.open("printpreview_helper.xul", "printpreview", "chrome,width=100,height=100");
-});
+window.open("printpreview_helper.xul", "printpreview", "chrome,width=100,height=100");
 ]]></script>
 </window>

--- a/layout/generic/crashtests/crashtests.list
+++ b/layout/generic/crashtests/crashtests.list
@@ -588,17 +588,17 @@ asserts(11) asserts-if(Android,274) load
 pref(font.size.inflation.minTwips,200) load 1032450.html
 load 1032613-1.svg
 load 1032613-2.html
 load 1037903.html
 load 1039454-1.html
 load 1042489.html
 load 1054010-1.html
 load 1058954-1.html
-skip-if(verify&&isDebugBuild&&(gtkWidget||OSX)) pref(dom.webcomponents.shadowdom.enabled,true) pref(dom.webcomponents.customelements.enabled,true) load 1059138-1.html
+skip-if(verify&&isDebugBuild&&(gtkWidget||OSX)) pref(dom.webcomponents.customelements.enabled,true) load 1059138-1.html
 load 1134531.html
 load 1134667.html
 load 1137723-1.html
 load 1137723-2.html
 load 1140268-1.html
 load 1145768.html
 load 1145931.html
 load 1146103.html

--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -1859,17 +1859,17 @@ pref(layout.css.moz-document.content.ena
 == 1053035-1-grid.html 1053035-1-ref.html
 == 1059167-1.html 1059167-1-ref.html
 fails-if(webrender) == 1059498-1.html 1059498-1-ref.html # WebRender: see bug 1504290
 fails-if(webrender) == 1059498-2.html 1059498-1-ref.html # WebRender: see bug 1504290
 fails-if(webrender) == 1059498-3.html 1059498-1-ref.html # WebRender: see bug 1499113
 == 1062108-1.html 1062108-1-ref.html
 == 1062792-1.html 1062792-1-ref.html
 == 1062963-floatmanager-reflow.html 1062963-floatmanager-reflow-ref.html
-test-pref(dom.webcomponents.shadowdom.enabled,true) == 1066554-1.html 1066554-1-ref.html
+== 1066554-1.html 1066554-1-ref.html
 == 1069716-1.html 1069716-1-ref.html
 == 1078262-1.html about:blank
 test-pref(layout.testing.overlay-scrollbars.always-visible,false) == 1081072-1.html 1081072-1-ref.html
 fuzzy-if(webrender,64-64,485-486) == 1081185-1.html 1081185-1-ref.html
 == 1097437-1.html 1097437-1-ref.html
 == 1103258-1.html 1103258-1-ref.html # assertion crash test with layers culling test
 == 1105137-1.html 1105137-1-ref.html
 fuzzy-if(d2d,0-36,0-304) fuzzy-if(/^Windows\x20NT\x2010\.0/.test(http.oscpu)&&d2d,0-139,0-701) == 1116480-1-fakeitalic-overflow.html 1116480-1-fakeitalic-overflow-ref.html

--- a/layout/reftests/mathml/reftest.list
+++ b/layout/reftests/mathml/reftest.list
@@ -362,17 +362,17 @@ fuzzy-if(OSX,0-1,0-100) fuzzy-if(skiaCon
 == mfrac-C-2.html mfrac-C-2-ref.html
 == mfrac-C-3.html mfrac-C-3-ref.html
 == mfrac-C-4.html mfrac-C-4-ref.html
 fuzzy-if(OSX,0-1,0-100) fuzzy-if(skiaContent,0-1,0-14) == mfrac-D-1.html mfrac-D-1-ref.html
 == mfrac-D-2.html mfrac-D-2-ref.html
 == mfrac-D-3.html mfrac-D-3-ref.html
 == mfrac-D-4.html mfrac-D-4-ref.html
 == mfrac-E-1.html mfrac-E-1-ref.html
-test-pref(dom.webcomponents.shadowdom.enabled,true) == shadow-dom-1.html shadow-dom-1-ref.html
+== shadow-dom-1.html shadow-dom-1-ref.html
 pref(dom.meta-viewport.enabled,true) pref(font.size.inflation.emPerLine,25) fuzzy-if(webrender&&!gtkWidget,0-255,0-244) == font-inflation-1.html font-inflation-1-ref.html
 test-pref(font.minimum-size.x-math,40) == default-font.html default-font-ref.html
 != radicalbar-1.html about:blank
 != radicalbar-1a.html about:blank
 != radicalbar-1b.html about:blank
 != radicalbar-1c.html about:blank
 != radicalbar-1d.html about:blank
 != radicalbar-2.html about:blank

--- a/layout/reftests/svg/reftest.list
+++ b/layout/reftests/svg/reftest.list
@@ -552,18 +552,18 @@ fuzzy-if(skiaContent,0-1,0-100) == tspan
 # currentColor override by color attribute
 == currentColor-override-flood.svg pass.svg
 == currentColor-override-lighting.svg currentColor-override-lighting-ref.svg
 == currentColor-override-stop.svg pass.svg
 
 == mask-invalidation.html mask-invalidation-ref.html
 
 # Shadow DOM id tracking.
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-1.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-2.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-3.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-4.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-5.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-6.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-7.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-8.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-9.html fragid-shadow-ref.html # Bug 1392106
-pref(dom.webcomponents.shadowdom.enabled,true) random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-10.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-1.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-2.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-3.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-4.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-5.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-6.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-7.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-8.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-9.html fragid-shadow-ref.html # Bug 1392106
+random-if(/^Windows\x20NT\x206\.1/.test(http.oscpu)) == fragid-shadow-10.html fragid-shadow-ref.html # Bug 1392106

--- a/layout/reftests/webcomponents/reftest.list
+++ b/layout/reftests/webcomponents/reftest.list
@@ -1,26 +1,26 @@
-pref(dom.webcomponents.shadowdom.enabled,true) == cross-tree-selection-1.html cross-tree-selection-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-shadow-1.html basic-shadow-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-shadow-2.html basic-shadow-2-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-shadow-3.html basic-shadow-3-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-shadow-4.html basic-shadow-4-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == fallback-content-1.html fallback-content-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == remove-insertion-point-1.html remove-insertion-point-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == nested-insertion-point-1.html nested-insertion-point-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == update-dist-node-descendants-1.html update-dist-node-descendants-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) fuzzy-if(Android,0-2,0-7) == input-transition-1.html input-transition-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == dynamic-insertion-point-distribution-1.html dynamic-insertion-point-distribution-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == dynamic-insertion-point-distribution-2.html dynamic-insertion-point-distribution-2-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == remove-append-shadow-host-1.html remove-append-shadow-host-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == reframe-shadow-child-1.html reframe-shadow-child-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == reframe-shadow-child-2.html reframe-shadow-child-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == style-sharing.html style-sharing-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == style-sharing-across-shadow.html style-sharing-ref.html # bug 1412400
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-slot-1.html basic-slot-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-slot-2.html basic-slot-2-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-slot-3.html basic-slot-3-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-slot-4.html basic-slot-3-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-slot-5.html basic-slot-5-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == basic-slot-6.html basic-slot-6-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == shadow-style-1.html shadow-style-1-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == shadow-style-2.html shadow-style-2-ref.html
-pref(dom.webcomponents.shadowdom.enabled,true) == shadow-style-3.html shadow-style-3-ref.html
+== cross-tree-selection-1.html cross-tree-selection-1-ref.html
+== basic-shadow-1.html basic-shadow-1-ref.html
+== basic-shadow-2.html basic-shadow-2-ref.html
+== basic-shadow-3.html basic-shadow-3-ref.html
+== basic-shadow-4.html basic-shadow-4-ref.html
+== fallback-content-1.html fallback-content-1-ref.html
+== remove-insertion-point-1.html remove-insertion-point-1-ref.html
+== nested-insertion-point-1.html nested-insertion-point-1-ref.html
+== update-dist-node-descendants-1.html update-dist-node-descendants-1-ref.html
+fuzzy-if(Android,0-2,0-7) == input-transition-1.html input-transition-1-ref.html
+== dynamic-insertion-point-distribution-1.html dynamic-insertion-point-distribution-1-ref.html
+== dynamic-insertion-point-distribution-2.html dynamic-insertion-point-distribution-2-ref.html
+== remove-append-shadow-host-1.html remove-append-shadow-host-1-ref.html
+== reframe-shadow-child-1.html reframe-shadow-child-ref.html
+== reframe-shadow-child-2.html reframe-shadow-child-ref.html
+== style-sharing.html style-sharing-ref.html
+== style-sharing-across-shadow.html style-sharing-ref.html # bug 1412400
+== basic-slot-1.html basic-slot-1-ref.html
+== basic-slot-2.html basic-slot-2-ref.html
+== basic-slot-3.html basic-slot-3-ref.html
+== basic-slot-4.html basic-slot-3-ref.html
+== basic-slot-5.html basic-slot-5-ref.html
+== basic-slot-6.html basic-slot-6-ref.html
+== shadow-style-1.html shadow-style-1-ref.html
+== shadow-style-2.html shadow-style-2-ref.html
+== shadow-style-3.html shadow-style-3-ref.html

--- a/layout/style/crashtests/crashtests.list
+++ b/layout/style/crashtests/crashtests.list
@@ -113,22 +113,22 @@ load 894245-1.html
 load 915440.html
 load 927734-1.html
 load 930270-1.html
 load 930270-2.html
 load 945048-1.html
 load 972199-1.html
 load 989965-1.html
 load 992333-1.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1017798-1.html
+load 1017798-1.html
 load 1028514-1.html
 load 1066089-1.html
 load 1074651-1.html
 load 1135534.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1089463-1.html
+load 1089463-1.html
 load 1136010-1.html
 load 1146101-1.html
 load 1153693-1.html
 load 1156969.svg
 load 1161320-1.html
 pref(dom.animations-api.getAnimations.enabled,true) load 1161320-2.html
 load 1161366-1.html
 load 1163446-1.html
@@ -268,30 +268,30 @@ load 1409931.html
 load 1410226-1.html
 load 1410226-2.html
 load 1411008.html
 load 1411143.html
 load 1411478.html
 load 1413288.html
 load 1413361.html
 load 1413670.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1415353.html
+load 1415353.html
 load 1418059.html
 test-pref(dom.animations-api.core.enabled,true) test-pref(dom.animations-api.implicit-keyframes.enabled,true) pref(dom.animations-api.getAnimations.enabled,true) load 1418867.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1419554.html
+load 1419554.html
 load 1426312.html
 load 1439793.html
 load 1409183.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1445682.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1449243.html
+load 1445682.html
+load 1449243.html
 load 1450691.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1453206.html
+load 1453206.html
 load 1454140.html
 load 1455108.html
 load 1457288.html
 load 1457985.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1468640.html
+load 1468640.html
 load 1469076.html
 load 1475003.html
 load 1479681.html
 load 1488817.html
 load 1490012.html
 load 1502893.html

--- a/layout/svg/crashtests/crashtests.list
+++ b/layout/svg/crashtests/crashtests.list
@@ -200,17 +200,17 @@ load 1223281-1.svg
 load 1322537-1.html
 load 1322537-2.html
 load 1322852.html
 load 1348564.svg
 load 1402109.html
 load 1402124.html
 load 1402486.html
 load 1421807-1.html
-pref(dom.webcomponents.shadowdom.enabled,true) load 1421807-2.html
+load 1421807-2.html
 load 1422226.html
 load 1443092.html
 load 1467552-1.html
 load 1474982.html
 load conditional-outer-svg-nondirty-reflow-assert.xhtml
 load extref-test-1.xhtml
 load blob-merging-and-retained-display-list.html
 load empty-blob-merging.html

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1420,17 +1420,16 @@ pref("dom.event.highrestimestamp.enabled
 pref("dom.event.coalesce_mouse_move",       true);
 
 #if defined(NIGHTLY_BUILD)
 pref("dom.ua_widget.enabled", true);
 #else
 pref("dom.ua_widget.enabled", false);
 #endif
 
-pref("dom.webcomponents.shadowdom.enabled", true);
 pref("dom.webcomponents.customelements.enabled", true);
 
 pref("javascript.enabled",                  true);
 pref("javascript.options.strict",           false);
 #ifdef DEBUG
 pref("javascript.options.strict.debug",     false);
 #endif
 pref("javascript.options.baselinejit",      true);

--- a/servo/components/style/gecko/selector_parser.rs
+++ b/servo/components/style/gecko/selector_parser.rs
@@ -342,20 +342,17 @@ impl<'a> SelectorParser<'a> {
 }
 
 impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
     type Impl = SelectorImpl;
     type Error = StyleParseErrorKind<'i>;
 
     #[inline]
     fn parse_slotted(&self) -> bool {
-        // NOTE(emilio): Slot assignment and such works per-document, but
-        // getting a document around here is not trivial, and it's not worth
-        // anyway to handle this in a per-doc basis.
-        unsafe { structs::nsContentUtils_sIsShadowDOMEnabled }
+        true
     }
 
     #[inline]
     fn parse_host(&self) -> bool {
         self.parse_slotted()
     }
 
     fn pseudo_element_allows_single_colon(name: &str) -> bool {

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_shadow_dom.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_shadow_dom.py
@@ -13,25 +13,23 @@ from marionette_driver.errors import (
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestShadowDom(MarionetteTestCase):
 
     def setUp(self):
         super(TestShadowDom, self).setUp()
-        self.marionette.set_pref("dom.webcomponents.shadowdom.enabled", True)
         self.marionette.navigate(self.marionette.absolute_url("test_shadow_dom.html"))
 
         self.host = self.marionette.find_element(By.ID, "host")
         self.marionette.switch_to_shadow_root(self.host)
         self.button = self.marionette.find_element(By.ID, "button")
 
     def tearDown(self):
-        self.marionette.clear_pref("dom.webcomponents.shadowdom.enabled")
         super(TestShadowDom, self).tearDown()
 
     def test_chrome_error(self):
         with self.marionette.using_context("chrome"):
             self.assertRaises(UnsupportedOperationException,
                               self.marionette.switch_to_shadow_root)
 
     def test_shadow_dom(self):

--- a/testing/profiles/unittest/user.js
+++ b/testing/profiles/unittest/user.js
@@ -116,17 +116,16 @@ user_pref("dom.successive_dialog_time_li
 // domains whitelisted for remote XUL, so that intranet apps and such continue
 // to work without major rewrites. However, we also use the whitelist mechanism
 // to run our XBL tests in automation, in which case we really want to be testing
 // the configuration that we ship to users without special whitelisting. So we
 // use an additional pref here to allow automation to use the "normal" behavior.
 user_pref("dom.use_xbl_scopes_for_remote_xul", true);
 user_pref("dom.w3c_touch_events.enabled", 1);
 user_pref("dom.webcomponents.customelements.enabled", true);
-user_pref("dom.webcomponents.shadowdom.enabled", true);
 user_pref("extensions.autoDisableScopes", 0);
 user_pref("extensions.blocklist.detailsURL", "http://{server}/extensions-dummy/blocklistDetailsURL");
 user_pref("extensions.blocklist.itemURL", "http://{server}/extensions-dummy/blocklistItemURL");
 user_pref("extensions.blocklist.url", "http://{server}/extensions-dummy/blocklistURL");
 // XPI extensions are required for test harnesses to load
 user_pref("extensions.defaultProviders.enabled", true);
 // Enable form autofill feature testing.
 user_pref("extensions.formautofill.available", "on");

--- a/testing/web-platform/meta/content-security-policy/securitypolicyviolation/targeting.html.ini
+++ b/testing/web-platform/meta/content-security-policy/securitypolicyviolation/targeting.html.ini
@@ -1,10 +1,9 @@
 [targeting.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   expected: TIMEOUT
   [Correct targeting inside shadow tree (inline handler).]
     disabled: https://bugzilla.mozilla.org/show_bug.cgi?id=1404842
 
   [Correct targeting inside shadow tree (style).]
     disabled: https://bugzilla.mozilla.org/show_bug.cgi?id=1404842
 
   [Elements created in this document, but pushed into a same-origin frame trigger on that frame's document, not on this frame's document.]

--- a/testing/web-platform/meta/css/css-backgrounds/background-size-027.html.ini
+++ b/testing/web-platform/meta/css/css-backgrounds/background-size-027.html.ini
@@ -1,4 +1,3 @@
 [background-size-027.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   disabled:
     if webrender: bug 1425588

--- a/testing/web-platform/meta/css/css-scoping/__dir__.ini
+++ b/testing/web-platform/meta/css/css-scoping/__dir__.ini
@@ -1,1 +1,1 @@
-prefs: [dom.animations-api.getAnimations.enabled:true, dom.webcomponents.shadowdom.enabled:true]
+prefs: [dom.animations-api.getAnimations.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/css/cssom-view/elementsFromPoint-shadowroot.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[elementsFromPoint-shadowroot.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/css/cssom-view/scrollIntoView-shadow.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[scrollIntoView-shadow.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/css/cssom/getComputedStyle-display-none-001.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[getComputedStyle-display-none-001.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/css/selectors/__dir__.ini
+++ /dev/null
@@ -1,1 +0,0 @@
-prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/custom-elements/CustomElementRegistry.html.ini
+++ b/testing/web-platform/meta/custom-elements/CustomElementRegistry.html.ini
@@ -1,10 +1,9 @@
 [CustomElementRegistry.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   [customElements.define must get callbacks of the constructor prototype]
     expected: FAIL
 
   [customElements.define must rethrow an exception thrown while getting callbacks on the constructor prototype]
     expected: FAIL
 
   [customElements.define must rethrow an exception thrown while converting a callback value to Function callback type]
     expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/custom-elements/adopted-callback.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[adopted-callback.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/custom-elements/connected-callbacks.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[connected-callbacks.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/custom-elements/custom-element-registry/upgrade.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[upgrade.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/custom-elements/disconnected-callbacks.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[disconnected-callbacks.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/custom-elements/reactions/Element.html.ini
+++ b/testing/web-platform/meta/custom-elements/reactions/Element.html.ini
@@ -1,10 +1,9 @@
 [Element.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   [removeAttribute on Element must not enqueue an attributeChanged reaction when removing an attribute that does not exist]
     expected: FAIL
 
   [removeAttributeNS on Element must not enqueue an attributeChanged reaction when removing an attribute that does not exist]
     expected: FAIL
 
   [removeAttributeNode on Element must not enqueue an attributeChanged reaction when removing an attribute that does not exist]
     expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/custom-elements/reactions/ShadowRoot.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[ShadowRoot.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/dom/events/event-global-extra.window.js.ini
+++ b/testing/web-platform/meta/dom/events/event-global-extra.window.js.ini
@@ -1,5 +1,5 @@
 [event-global-extra.window.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true, dom.window.event.enabled:true]
+  prefs: [dom.window.event.enabled:true]
   [Listener from a different global]
     expected: FAIL

--- a/testing/web-platform/meta/dom/events/event-global.html.ini
+++ b/testing/web-platform/meta/dom/events/event-global.html.ini
@@ -1,2 +1,2 @@
 [event-global.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true, dom.window.event.enabled:true]
+  prefs: [dom.window.event.enabled:true]

--- a/testing/web-platform/meta/dom/events/relatedTarget.window.js.ini
+++ b/testing/web-platform/meta/dom/events/relatedTarget.window.js.ini
@@ -1,8 +1,7 @@
 [relatedTarget.window.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   [Reset targets before activation behavior]
     expected: FAIL
 
   [Retarget a shadow-tree relatedTarget]
     expected: FAIL

--- a/testing/web-platform/meta/dom/interfaces.html.ini
+++ b/testing/web-platform/meta/dom/interfaces.html.ini
@@ -1,10 +1,9 @@
 [interfaces.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   [Document interface: attribute origin]
     expected: FAIL
     bug: 931884
 
   [Document interface: xmlDoc must inherit property "origin" with the proper type (3)]
     expected: FAIL
     bug: 931884

--- a/testing/web-platform/meta/html/dom/reflection-misc.html.ini
+++ b/testing/web-platform/meta/html/dom/reflection-misc.html.ini
@@ -1,10 +1,10 @@
 [reflection-misc.html]
-  prefs: [dom.dialog_element.enabled: true, dom.webcomponents.shadowdom.enabled:true]
+  prefs: [dom.dialog_element.enabled: true]
   [html.tabIndex: setAttribute() to object "3" followed by getAttribute()]
     expected: FAIL
 
   [html.tabIndex: setAttribute() to object "3" followed by IDL get]
     expected: FAIL
 
   [script.tabIndex: setAttribute() to object "3" followed by getAttribute()]
     expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/html/semantics/document-metadata/the-meta-element/pragma-directives/attr-meta-http-equiv-refresh/not-in-shadow-tree.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[not-in-shadow-tree.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/html/semantics/forms/the-form-element/form-elements-filter.html.ini
+++ b/testing/web-platform/meta/html/semantics/forms/the-form-element/form-elements-filter.html.ini
@@ -1,3 +1,2 @@
 [form-elements-filter.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   max-asserts: 3

deleted file mode 100644
--- a/testing/web-platform/meta/html/semantics/forms/the-label-element/label-attributes.sub.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[label-attributes.sub.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/html/semantics/interfaces.html.ini
+++ b/testing/web-platform/meta/html/semantics/interfaces.html.ini
@@ -1,10 +1,10 @@
 [interfaces.html]
-  prefs: [dom.dialog_element.enabled: true, dom.webcomponents.shadowdom.enabled:true]
+  prefs: [dom.dialog_element.enabled: true]
   [Interfaces for image]
     expected: FAIL
 
   [Interfaces for keygen]
     expected: FAIL
 
   [Interfaces for IMAGE]
     expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/intersection-observer/shadow-content.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shadow-content.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/payment-request/interfaces.https.html.ini
+++ b/testing/web-platform/meta/payment-request/interfaces.https.html.ini
@@ -1,10 +1,9 @@
 [interfaces.https.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   [PaymentRequest interface: existence and properties of interface object]
     expected:
       if not e10s: FAIL
 
   [PaymentRequest interface object length]
     expected:
       if not e10s: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/shadow-dom/__dir__.ini
+++ /dev/null
@@ -1,1 +0,0 @@
-prefs: [dom.webcomponents.shadowdom.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/shadow-dom/untriaged/events/event-dispatch/test-003.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[test-003.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]

--- a/testing/web-platform/meta/touch-events/touch-retargeting.html.ini
+++ b/testing/web-platform/meta/touch-events/touch-retargeting.html.ini
@@ -1,5 +1,4 @@
 [touch-retargeting.html]
-  prefs: [dom.webcomponents.shadowdom.enabled:true]
   [TouchEvent's touches, targetTouches, and changedTouches should be retargeted.]
     expected: FAIL

--- a/toolkit/components/extensions/test/xpcshell/test_ext_shadowdom.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_shadowdom.js
@@ -1,39 +1,20 @@
 "use strict";
 
-ChromeUtils.defineModuleGetter(this, "Preferences",
-                               "resource://gre/modules/Preferences.jsm");
-
 // ExtensionContent.jsm needs to know when it's running from xpcshell,
 // to use the right timeout for content scripts executed at document_idle.
 ExtensionTestUtils.mockAppInfo();
 
 const server = createHttpServer();
 server.registerDirectory("/data/", do_get_file("data"));
 
 const BASE_URL = `http://localhost:${server.identity.primaryPort}/data`;
 
 add_task(async function test_contentscript_shadowDOM() {
-  const PREFS = {
-    "dom.webcomponents.shadowdom.enabled": true,
-  };
-
-  // Set prefs to our initial values.
-  for (let pref in PREFS) {
-    Preferences.set(pref, PREFS[pref]);
-  }
-
-  registerCleanupFunction(() => {
-    // Reset the prefs.
-    for (let pref in PREFS) {
-      Preferences.reset(pref);
-    }
-  });
-
   function backgroundScript() {
     browser.test.assertTrue("openOrClosedShadowRoot" in document.documentElement,
                             "Should have openOrClosedShadowRoot in Element in background script.");
   }
 
   function contentScript() {
     let host = document.getElementById("host");
     browser.test.assertTrue("openOrClosedShadowRoot" in host, "Should have openOrClosedShadowRoot in Element.");

--- a/toolkit/components/tooltiptext/tests/browser_shadow_dom_tooltip.js
+++ b/toolkit/components/tooltiptext/tests/browser_shadow_dom_tooltip.js
@@ -1,14 +1,13 @@
 /* eslint-disable mozilla/no-arbitrary-setTimeout */
 
 add_task(async function setup() {
   await SpecialPowers.pushPrefEnv(
-    {"set": [["ui.tooltipDelay", 0],
-             ["dom.webcomponents.shadowdom.enabled", true]]});
+    {"set": [["ui.tooltipDelay", 0]]});
 });
 
 add_task(async function test_title_in_shadow_dom() {
   let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
 
   info("Moving mouse out of the way.");
   await EventUtils.synthesizeAndWaitNativeMouseMove(tab.linkedBrowser, 300, 300);

--- a/toolkit/content/tests/widgets/chrome.ini
+++ b/toolkit/content/tests/widgets/chrome.ini
@@ -1,12 +1,11 @@
 [DEFAULT]
 prefs =
   dom.ua_widget.enabled=true
-  dom.webcomponents.shadowdom.enabled=true
 skip-if = os == 'android'
 support-files =
   tree_shared.js
   popup_shared.js
   window_label_checkbox.xul
   window_menubar.xul
   seek_with_sound.ogg

--- a/toolkit/content/tests/widgets/mochitest.ini
+++ b/toolkit/content/tests/widgets/mochitest.ini
@@ -1,12 +1,11 @@
 [DEFAULT]
 prefs =
   dom.ua_widget.enabled=true
-  dom.webcomponents.shadowdom.enabled=true
 support-files =
   audio.wav
   audio.ogg
   file_videocontrols_jsdisabled.html
   seek_with_sound.ogg
   video.ogg
   head.js
   tree_shared.js

☠☠ backed out by 0210ae2d20cc ☠ ☠
author	Timothy Guan-tin Chien <timdream@gmail.com>
	Wed, 14 Nov 2018 19:34:52 +0000
changeset 505623	7b845eac9dd726c7213024ccb94b009da5674592
parent 505622	2170be698d4b5b7e9da804ce8c98275eade1e8f1
child 505624	06b12fd41ff14bbcba2d2bf268ad5da44496a02a
push id	1905
push user	ffxbld-merge
push date	Mon, 21 Jan 2019 12:33:13 +0000
treeherder	mozilla-release@c2fca1944d8c [default view] [failures only]
perfherder	[talos] [build metrics] [platform microbench] (compared to previous push)
reviewers	smaug
bugs	1503019
milestone	65.0a1
first release with	nightly linux32 dca9c72df68b / 65.0a1 / 20181115100051 / files nightly linux64 dca9c72df68b / 65.0a1 / 20181115100051 / files nightly mac dca9c72df68b / 65.0a1 / 20181115100051 / files nightly win32 dca9c72df68b / 65.0a1 / 20181115100051 / files nightly win64 dca9c72df68b / 65.0a1 / 20181115100051 / files
last release without	nightly linux32 073045259e75 / 65.0a1 / 20181114100226 / files nightly linux64 073045259e75 / 65.0a1 / 20181114100226 / files nightly mac 073045259e75 / 65.0a1 / 20181114100226 / files nightly win32 073045259e75 / 65.0a1 / 20181114100226 / files nightly win64 073045259e75 / 65.0a1 / 20181114100226 / files

accessible/tests/mochitest/elm/test_shadowroot.html		file \| annotate \| diff \| comparison \| revisions
accessible/tests/mochitest/hittest/test_shadowroot.html		file \| annotate \| diff \| comparison \| revisions
accessible/tests/mochitest/relations/test_shadowdom.html		file \| annotate \| diff \| comparison \| revisions
accessible/tests/mochitest/treeupdate/test_bug1276857.html		file \| annotate \| diff \| comparison \| revisions
browser/base/content/test/general/browser_contentAltClick.js		file \| annotate \| diff \| comparison \| revisions
browser/base/content/test/general/browser_contextmenu.js		file \| annotate \| diff \| comparison \| revisions
browser/components/extensions/test/browser/browser_ext_menus_replace_menu.js		file \| annotate \| diff \| comparison \| revisions
browser/components/extensions/test/browser/browser_ext_menus_targetElement_shadow.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/inspector/markup/test/browser_markup_anonymous_03.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/inspector/markup/test/browser_markup_dragdrop_invalidNodes.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/inspector/markup/test/browser_markup_shadowdom_navigation.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/inspector/markup/test/head.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/inspector/rules/test/browser_rules_shadowdom_slot_rules.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/inspector/test/browser_inspector_breadcrumbs_shadowdom.js		file \| annotate \| diff \| comparison \| revisions
devtools/client/locales/en-US/inspector.properties		file \| annotate \| diff \| comparison \| revisions
devtools/client/shared/test/shared-head.js		file \| annotate \| diff \| comparison \| revisions
devtools/server/tests/mochitest/test_inspector-anonymous.html		file \| annotate \| diff \| comparison \| revisions
dom/base/ChildIterator.cpp		file \| annotate \| diff \| comparison \| revisions
dom/base/DocumentOrShadowRoot.cpp		file \| annotate \| diff \| comparison \| revisions
dom/base/crashtests/1324463.html		file \| annotate \| diff \| comparison \| revisions
dom/base/crashtests/1422931.html		file \| annotate \| diff \| comparison \| revisions
dom/base/crashtests/crashtests.list		file \| annotate \| diff \| comparison \| revisions
dom/base/nsContentUtils.cpp		file \| annotate \| diff \| comparison \| revisions
dom/base/nsContentUtils.h		file \| annotate \| diff \| comparison \| revisions
dom/base/nsDocument.cpp		file \| annotate \| diff \| comparison \| revisions
dom/base/nsDocument.h		file \| annotate \| diff \| comparison \| revisions
dom/base/nsFocusManager.cpp		file \| annotate \| diff \| comparison \| revisions
dom/base/nsIDocument.h		file \| annotate \| diff \| comparison \| revisions
dom/base/nsTextNode.cpp		file \| annotate \| diff \| comparison \| revisions
dom/base/nsTextNode.h		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_bug1025933.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_bug1037687.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_bug1100912.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_bug1421568.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_bug1453693.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_bug1472427.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_find.html		file \| annotate \| diff \| comparison \| revisions
dom/base/test/test_range_bounds.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1079236.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1145910.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1150308.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1264380.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1429572.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1446834.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_bug1484371.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_slotted_mouse_event.html		file \| annotate \| diff \| comparison \| revisions
dom/events/test/test_slotted_text_click.html		file \| annotate \| diff \| comparison \| revisions
dom/html/HTMLSlotElement.cpp		file \| annotate \| diff \| comparison \| revisions
dom/html/test/test_bug1472426.html		file \| annotate \| diff \| comparison \| revisions
dom/html/test/test_fullscreen-api.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/pointerlock/test_pointerlock-api.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/head.js		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_bug1269155.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_custom_element_in_shadow.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_detached_style.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_document_adoptnode.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_document_importnode.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_event_retarget.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_event_stopping.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_shadowroot.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_shadowroot_clonenode.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_shadowroot_inert_element.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_shadowroot_style.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_shadowroot_style_order.html		file \| annotate \| diff \| comparison \| revisions
dom/tests/mochitest/webcomponents/test_style_fallback_content.html		file \| annotate \| diff \| comparison \| revisions
dom/webidl/Element.webidl		file \| annotate \| diff \| comparison \| revisions
dom/webidl/HTMLSlotElement.webidl		file \| annotate \| diff \| comparison \| revisions
dom/webidl/ShadowRoot.webidl		file \| annotate \| diff \| comparison \| revisions
dom/webidl/Text.webidl		file \| annotate \| diff \| comparison \| revisions
dom/xml/nsXMLPrettyPrinter.cpp		file \| annotate \| diff \| comparison \| revisions
dom/xml/resources/XMLPrettyPrint.xml		file \| annotate \| diff \| comparison \| revisions
dom/xml/resources/jar.mn		file \| annotate \| diff \| comparison \| revisions
layout/base/crashtests/crashtests.list		file \| annotate \| diff \| comparison \| revisions
layout/base/tests/chrome/test_printpreview.xul		file \| annotate \| diff \| comparison \| revisions
layout/generic/crashtests/crashtests.list		file \| annotate \| diff \| comparison \| revisions
layout/reftests/bugs/reftest.list		file \| annotate \| diff \| comparison \| revisions
layout/reftests/mathml/reftest.list		file \| annotate \| diff \| comparison \| revisions
layout/reftests/svg/reftest.list		file \| annotate \| diff \| comparison \| revisions
layout/reftests/webcomponents/reftest.list		file \| annotate \| diff \| comparison \| revisions
layout/style/crashtests/crashtests.list		file \| annotate \| diff \| comparison \| revisions
layout/svg/crashtests/crashtests.list		file \| annotate \| diff \| comparison \| revisions
modules/libpref/init/all.js		file \| annotate \| diff \| comparison \| revisions
servo/components/style/gecko/selector_parser.rs		file \| annotate \| diff \| comparison \| revisions
testing/marionette/harness/marionette_harness/tests/unit/test_shadow_dom.py		file \| annotate \| diff \| comparison \| revisions
testing/profiles/unittest/user.js		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/content-security-policy/securitypolicyviolation/targeting.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/css/css-backgrounds/background-size-027.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/css/css-scoping/__dir__.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/css/cssom-view/elementsFromPoint-shadowroot.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/css/cssom-view/scrollIntoView-shadow.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/css/cssom/getComputedStyle-display-none-001.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/css/selectors/__dir__.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/CustomElementRegistry.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/adopted-callback.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/connected-callbacks.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/custom-element-registry/upgrade.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/disconnected-callbacks.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/reactions/Element.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/custom-elements/reactions/ShadowRoot.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/dom/events/event-global-extra.window.js.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/dom/events/event-global.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/dom/events/relatedTarget.window.js.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/dom/interfaces.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/html/dom/reflection-misc.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/html/semantics/document-metadata/the-meta-element/pragma-directives/attr-meta-http-equiv-refresh/not-in-shadow-tree.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/html/semantics/forms/the-form-element/form-elements-filter.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/html/semantics/forms/the-label-element/label-attributes.sub.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/html/semantics/interfaces.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/intersection-observer/shadow-content.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/payment-request/interfaces.https.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/shadow-dom/__dir__.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/shadow-dom/untriaged/events/event-dispatch/test-003.html.ini		file \| annotate \| diff \| comparison \| revisions
testing/web-platform/meta/touch-events/touch-retargeting.html.ini		file \| annotate \| diff \| comparison \| revisions
toolkit/components/extensions/test/xpcshell/test_ext_shadowdom.js		file \| annotate \| diff \| comparison \| revisions
toolkit/components/tooltiptext/tests/browser_shadow_dom_tooltip.js		file \| annotate \| diff \| comparison \| revisions
toolkit/content/tests/widgets/chrome.ini		file \| annotate \| diff \| comparison \| revisions
toolkit/content/tests/widgets/mochitest.ini		file \| annotate \| diff \| comparison \| revisions