Auto merge of #14241 - Manishearth:mut-cssom, r=SimonSapin

CSSOM: Whole ton of things

CSSOM is now starting to be useful!

Based on #14190. Only the <s>last commit</s> last two commits need review.

cc @xidorn . This doesn't change the style API, but adds useful methods.

part of #11420

This adds:
 - `insertRule()` and `deleteRule()` on `CSSStyleSheet`, `CSSGroupingRule`
 - `.style` getters on link and style elements
 - Keyframes-backed `CSSRules` and `CSSKeyframesRule.cssRules`
 - `CSSGroupingRule.cssRules`
 - `prefix` and `namespaceURI` attributes of `CSSNamespaceRule`
 - Fixups regarding parent stylesheets

r? @SimonSapin

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1 files changed, 2 insertions, 2 deletions

diff --git a/components/script/dom/webidls/CSSNamespaceRule.webidl b/components/script/dom/webidls/CSSNamespaceRule.webidl
index a8d6b61548f..aa1ce87e289 100644
--- a/components/script/dom/webidls/CSSNamespaceRule.webidl
+++ b/components/script/dom/webidls/CSSNamespaceRule.webidl
@@ -5,6 +5,6 @@
 // https://drafts.csswg.org/cssom/#the-cssnamespacerule-interface
 [Exposed=Window]
 interface CSSNamespaceRule : CSSRule {
-  // readonly attribute DOMString namespaceURI;
-  // readonly attribute DOMString prefix;
+  readonly attribute DOMString namespaceURI;
+  readonly attribute DOMString prefix;
 };