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-device-adapt.idl b/node_modules/@webref/idl/css-device-adapt.idl
new file mode 100644
index 0000000..bfd4a6d
--- /dev/null
+++ b/node_modules/@webref/idl/css-device-adapt.idl
@@ -0,0 +1,13 @@
+// GENERATED CONTENT - DO NOT EDIT
+// Content was automatically extracted by Reffy into webref
+// (https://github.com/w3c/webref)
+// Source: CSS Device Adaptation Module Level 1 (https://drafts.csswg.org/css-device-adapt/)
+
+partial interface CSSRule {
+    const unsigned short VIEWPORT_RULE = 15;
+};
+
+[Exposed=Window]
+interface CSSViewportRule : CSSRule {
+    readonly attribute CSSStyleDeclaration style;
+};