Make <menuitem> pref-controlled and disable by default.

dom/html/HTMLMenuElement.cpp

@@ -137,9 +137,9 @@ HTMLMenuElement::ParseAttribute(int32_t aNamespaceID,
                                 const nsAString& aValue,
                                 nsAttrValue& aResult)
 {
-  if (aNamespaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::type) {
+  if (aNamespaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::type &&
-    bool success = aResult.ParseEnumValue(aValue, kMenuTypeTable,
+      Preferences::GetBool("dom.menuitem.enabled")) {
-                                            false);
+    bool success = aResult.ParseEnumValue(aValue, kMenuTypeTable, false);
     if (success) {
       mType = aResult.GetEnumValue();
     } else {

dom/html/HTMLMenuItemElement.cpp

@@ -7,12 +7,21 @@
 
 #include "mozilla/BasicEvents.h"
 #include "mozilla/EventDispatcher.h"
+#include "mozilla/Preferences.h"
 #include "mozilla/dom/HTMLMenuItemElementBinding.h"
+#include "mozilla/dom/HTMLUnknownElement.h"
 #include "nsAttrValueInlines.h"
 #include "nsContentUtils.h"
 
-
+nsGenericHTMLElement*
-NS_IMPL_NS_NEW_HTML_ELEMENT_CHECK_PARSER(MenuItem)
+NS_NewHTMLMenuItemElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
+                          mozilla::dom::FromParser aFromParser) {
+  if (mozilla::Preferences::GetBool("dom.menuitem.enabled")) {
+    return new mozilla::dom::HTMLMenuItemElement(aNodeInfo, aFromParser);
+  } else {
+    return new mozilla::dom::HTMLUnknownElement(aNodeInfo);
+  }
+}
 
 namespace mozilla {
 namespace dom {

dom/html/test/browser_content_contextmenu_userinput.js

@@ -4,6 +4,9 @@ const kPage = "http://example.org/browser/" +
               "dom/html/test/file_content_contextmenu.html";
 
 add_task(function* () {
+  yield SpecialPowers.pushPrefEnv({
+    set: [["dom.menuitem.enabled", true]],
+  });
   yield BrowserTestUtils.withNewTab({
     gBrowser,
     url: kPage

dom/html/test/mochitest.ini

@@ -1,4 +1,6 @@
 [DEFAULT]
+prefs = 
+  dom.menuitem.enabled=true # only for test_bug617528.html
 support-files =
   347174transform.xsl
   347174transformable.xml

dom/tests/mochitest/general/test_interfaces.html

@@ -496,8 +496,6 @@ var interfaceNamesInGlobalScope =
     "HTMLMediaElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLMenuElement",
-// IMPORTANT: Do not change this list without review from a DOM peer!
-    "HTMLMenuItemElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "HTMLMetaElement",
 // IMPORTANT: Do not change this list without review from a DOM peer!

dom/tests/mochitest/webcomponents/htmlconstructor_builtin_tests.js

@@ -71,7 +71,6 @@
   ['map', 'Map'],
   ['mark', ''],
   ['menu', 'Menu'],
-  ['menuitem', 'MenuItem'],
   ['meta', 'Meta'],
   ['meter', 'Meter'],
   ['nav', ''],

dom/webidl/EventHandler.webidl

@@ -82,6 +82,7 @@ interface GlobalEventHandlers {
            attribute EventHandler onseeked;
            attribute EventHandler onseeking;
            attribute EventHandler onselect;
+           [Pref="dom.menuitem.enabled"]
            attribute EventHandler onshow;
            //(Not implemented)attribute EventHandler onsort;
            attribute EventHandler onstalled;

dom/webidl/HTMLElement.webidl

@@ -49,10 +49,8 @@ interface HTMLElement : Element {
            attribute DOMString contentEditable;
   [Pure]
   readonly attribute boolean isContentEditable;
-  [Pure]
+  [Pure, Pref="dom.menuitem.enabled"]
   readonly attribute HTMLMenuElement? contextMenu;
-  //[SetterThrows]
-  //         attribute HTMLMenuElement? contextMenu;
   [CEReactions, SetterThrows, Pure]
            attribute boolean spellcheck;
 

dom/webidl/HTMLMenuElement.webidl

@@ -17,9 +17,9 @@ interface MenuBuilder;
 // http://www.whatwg.org/specs/web-apps/current-work/#the-menu-element
 [HTMLConstructor]
 interface HTMLMenuElement : HTMLElement {
-           [CEReactions, SetterThrows]
+           [CEReactions, SetterThrows, Pref="dom.menuitem.enabled"]
            attribute DOMString type;
-           [CEReactions, SetterThrows]
+           [CEReactions, SetterThrows, Pref="dom.menuitem.enabled"]
            attribute DOMString label;
 };
 

dom/webidl/HTMLMenuItemElement.webidl

@@ -12,7 +12,7 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-menuitem-element
-[HTMLConstructor]
+[HTMLConstructor, Pref="dom.menuitem.enabled"]
 interface HTMLMenuItemElement : HTMLElement {
            [CEReactions, SetterThrows]
            attribute DOMString type;

layout/style/res/html.css

@@ -576,8 +576,10 @@ ul, menu, dir {
   padding-inline-start: 40px;
 }
 
-menu[type="context"] {
+@supports -moz-bool-pref("dom.menuitem.enabled") {
-  display: none !important;
+  menu[type="context"] {
+    display: none !important;
+  }
 }
 
 ol {

modules/libpref/init/all.js

@@ -4978,6 +4978,9 @@ pref("dom.mozInputMethod.enabled", false);
 // Enable mapped array buffer by default.
 pref("dom.mapped_arraybuffer.enabled", true);
 
+// Whether <menuitem> is a thing or not.
+pref("dom.menuitem.enabled", false);
+
 #ifdef MOZ_SAFE_BROWSING
 // The tables used for Safebrowsing phishing and malware checks.
 pref("urlclassifier.malwareTable", "goog-malware-shavar,goog-unwanted-shavar,test-malware-simple,test-unwanted-simple");