Only restyle viewport-relative nodes on viewport size change

components/style/properties/properties.mako.rs

@@ -32,6 +32,7 @@ use parser::{ParserContext, ParserContextExtraData, log_css_error};
 use selectors::matching::DeclarationBlock;
 use stylesheets::Origin;
 use values::LocalToCss;
+use values::HasViewportPercentage;
 use values::computed::{self, TContext, ToComputedValue};
 use values::specified::BorderStyle;
 
@@ -825,6 +826,19 @@ impl ToCss for PropertyDeclaration {
     }
 }
 
+impl HasViewportPercentage for PropertyDeclaration {
+    fn has_viewport_percentage(&self) -> bool {
+        match *self {
+            % for property in data.longhands:
+                PropertyDeclaration::${property.camel_case}(DeclaredValue::Value(ref val)) => {
+                    val.has_viewport_percentage()
+                },
+            % endfor
+            _ => false
+        }
+    }
+}
+
 impl PropertyDeclaration {
     pub fn name(&self) -> PropertyDeclarationName {
         match *self {