Add @webref/idl dependency

Signed-off-by: Victor Porof <victorporof@chromium.org>
Bug: 1325812
Change-Id: I044170880d20ce0402062755787cccafd63c6a42
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3695370
Reviewed-by: Mathias Bynens <mathias@chromium.org>
diff --git a/node_modules/@webref/idl/css-nesting.idl b/node_modules/@webref/idl/css-nesting.idl
new file mode 100644
index 0000000..8d3cccb
--- /dev/null
+++ b/node_modules/@webref/idl/css-nesting.idl
@@ -0,0 +1,19 @@
+// GENERATED CONTENT - DO NOT EDIT
+// Content was automatically extracted by Reffy into webref
+// (https://github.com/w3c/webref)
+// Source: CSS Nesting Module (https://drafts.csswg.org/css-nesting/)
+
+partial interface CSSStyleRule {
+  [SameObject] readonly attribute CSSRuleList cssRules;
+  unsigned long insertRule(CSSOMString rule, optional unsigned long index = 0);
+  undefined deleteRule(unsigned long index);
+};
+
+[Exposed=Window]
+interface CSSNestingRule : CSSRule {
+  attribute CSSOMString selectorText;
+  [SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+  [SameObject] readonly attribute CSSRuleList cssRules;
+  unsigned long insertRule(CSSOMString rule, optional unsigned long index = 0);
+  undefined deleteRule(unsigned long index);
+};