style: Support the all shorthand.

Fixes #15055.

components/script/dom/webidls/CSSStyleDeclaration.webidl

@@ -33,6 +33,8 @@ interface CSSStyleDeclaration {
 };
 
 partial interface CSSStyleDeclaration {
+  [SetterThrows, TreatNullAs=EmptyString] attribute DOMString all;
+
   [SetterThrows, TreatNullAs=EmptyString] attribute DOMString background;
   [SetterThrows, TreatNullAs=EmptyString] attribute DOMString backgroundColor;
   [SetterThrows, TreatNullAs=EmptyString] attribute DOMString background-color;

components/style/properties/data.py

@@ -280,3 +280,6 @@ def declare_shorthand(self, name, sub_properties, products="gecko servo",
         self.add_prefixed_aliases(shorthand)
         self.shorthands.append(shorthand)
         return shorthand
+
+    def shorthands_except_all(self):
+        return [s for s in self.shorthands if s.name != "all"]

components/style/properties/properties.mako.rs

@@ -165,6 +165,45 @@ pub mod shorthands {
     <%include file="/shorthand/position.mako.rs" />
     <%include file="/shorthand/inherited_svg.mako.rs" />
     <%include file="/shorthand/text.mako.rs" />
+
+    // We don't defined the 'all' shorthand using the regular helpers:shorthand
+    // mechanism, since it causes some very large types to be generated.
+    <% data.declare_shorthand("all",
+                              [p.name for p in data.longhands if p.name not in ['direction', 'unicode-bidi']],
+                              spec="https://drafts.csswg.org/css-cascade-3/#all-shorthand") %>
+    pub mod all {
+        use cssparser::Parser;
+        use parser::ParserContext;
+        use properties::{ParsedDeclaration, ShorthandId, UnparsedValue};
+        use std::sync::Arc;
+
+        pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<ParsedDeclaration, ()> {
+            // This function is like the parse() that is generated by
+            // helpers:shorthand, but since the only values for the 'all'
+            // shorthand when not just a single CSS-wide keyword is one
+            // with variable references, we can make this function a
+            // little simpler.
+            //
+            // FIXME(heycam) Try to share code with the helpers:shorthand
+            // definition.
+            input.look_for_var_functions();
+            let start = input.position();
+            while let Ok(_) = input.next() {}  // Look for var()
+            if input.seen_var_functions() {
+                input.reset(start);
+                let (first_token_type, css) = try!(
+                    ::custom_properties::parse_non_custom_with_var(input));
+                Ok(ParsedDeclaration::AllWithVariables(Arc::new(UnparsedValue {
+                    css: css.into_owned(),
+                    first_token_type: first_token_type,
+                    url_data: context.url_data.clone(),
+                    from_shorthand: Some(ShorthandId::All),
+                })))
+            } else {
+                Err(())
+            }
+        }
+    }
 }
 
 /// A module with all the code related to animated properties.
@@ -337,7 +376,12 @@ impl PropertyDeclarationIdSet {
                                 longhands::${property.ident}
                                          ::parse_specified(&context, input).map(DeclaredValueOwned::Value)
                             }
-                            % for shorthand in data.shorthands:
+                            Some(ShorthandId::All) => {
+                                // No need to parse the 'all' shorthand as anything other than a CSS-wide
+                                // keyword, after variable substitution.
+                                Err(())
+                            }
+                            % for shorthand in data.shorthands_except_all():
                                 % if property in shorthand.sub_properties:
                                     Some(ShorthandId::${shorthand.camel_case}) => {
                                         shorthands::${shorthand.ident}::parse_value(&context, input)
@@ -543,7 +587,14 @@ impl ShorthandId {
               I: Iterator<Item=&'a PropertyDeclaration>,
     {
         match *self {
-            % for property in data.shorthands:
+            ShorthandId::All => {
+                // No need to try to serialize the declarations as the 'all'
+                // shorthand, since it only accepts CSS-wide keywords (and
+                // variable references), which will be handled in
+                // get_shorthand_appendable_value.
+                Err(fmt::Error)
+            }
+            % for property in data.shorthands_except_all():
                 ShorthandId::${property.camel_case} => {
                     match shorthands::${property.ident}::LonghandsToSerialize::from_iter(declarations) {
                         Ok(longhands) => longhands.to_css(dest),
@@ -868,8 +919,14 @@ impl PropertyId {
 /// Includes shorthands before expansion
 pub enum ParsedDeclaration {
     % for shorthand in data.shorthands:
+        % if shorthand.name == "all":
+        // No need for an All(shorthands::all::Longhands) case, since we can
+        // never have any values for 'all' other than the CSS-wide keywords
+        // and values with variable references.
+        % else:
         /// ${shorthand.name}
         ${shorthand.camel_case}(shorthands::${shorthand.ident}::Longhands),
+        % endif
 
         /// ${shorthand.name} with a CSS-wide keyword
         ${shorthand.camel_case}CSSWideKeyword(CSSWideKeyword),
@@ -910,6 +967,7 @@ impl ParsedDeclaration {
                    overwrite_more_important: bool) -> bool {
         match self {
             % for shorthand in data.shorthands:
+                % if shorthand.name != "all":
                 ParsedDeclaration::${shorthand.camel_case}(
                     shorthands::${shorthand.ident}::Longhands {
                         % for sub_property in shorthand.sub_properties:
@@ -933,6 +991,7 @@ impl ParsedDeclaration {
                     % endfor
                     changed
                 },
+                % endif
                 ParsedDeclaration::${shorthand.camel_case}CSSWideKeyword(keyword) => {
                     let mut changed = false;
                     % for sub_property in shorthand.sub_properties: