Auto merge of #16530 - metajack:kill-domrectlist, r=nox

Remove DOMRectList and use sequences instead.

DOMRectList was removed last back in 2015. See
https://www.w3.org/Bugs/Public/show_bug.cgi?id=26200 for details.

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components/script/dom/webidls/DOMRectList.webidl

@@ -1,11 +0,0 @@
-/* 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/. */
-
-// http://dev.w3.org/fxtf/geometry/#DOMRectList
-[NoInterfaceObject, Exposed=(Window,Worker)]
-//[ArrayClass]
-interface DOMRectList {
-  readonly attribute unsigned long length;
-  getter DOMRect? item(unsigned long index);
-};

components/script/dom/webidls/Element.webidl

@@ -81,7 +81,8 @@ interface Element : Node {
 
 // http://dev.w3.org/csswg/cssom-view/#extensions-to-the-element-interface
 partial interface Element {
-  DOMRectList getClientRects();
+  sequence<DOMRect> getClientRects();
+  [NewObject]
   DOMRect getBoundingClientRect();
 
   void scroll(optional ScrollToOptions options);

components/script/dom/webidls/Range.webidl

@@ -82,6 +82,7 @@ partial interface Range {
 
 // http://dev.w3.org/csswg/cssom-view/#extensions-to-the-range-interface
 partial interface Range {
-  // DOMRectList? getClientRects();
+  // sequence<DOMRect> getClientRects();
+  // [NewObject]
   // DOMRect getBoundingClientRect();
 };