style: Generate ComputedStyleMap entry list from property data.

This changes the order of properties returned from gCS. The old order
doesn't make much sense, and other browsers don't agree on an identical
order either, so it should be trivial to change it. Also the spec isn't
super clear / useful in this case.

Several -moz-prefixed properties are excluded from the list due to their
being internal. I suspect they are never accessible anyway, so probably
nothing gets changed by this.

Bug: 1471114
Reviewed-by: xidorn
MozReview-Commit-ID: 9LfangjpJ3P

components/style/properties/properties.mako.rs

@@ -836,6 +836,8 @@ bitflags! {
          * they can be checked in the C++ side via ServoCSSPropList.h. */
         /// This property can be animated on the compositor.
         const CAN_ANIMATE_ON_COMPOSITOR = 0;
+        /// This shorthand property is accessible from getComputedStyle.
+        const SHORTHAND_IN_GETCS = 0;
     }
 }
 

components/style/properties/shorthands/background.mako.rs

@@ -196,6 +196,7 @@
 </%helpers:shorthand>
 
 <%helpers:shorthand name="background-position"
+                    flags="SHORTHAND_IN_GETCS"
                     sub_properties="background-position-x background-position-y"
                     spec="https://drafts.csswg.org/css-backgrounds-4/#the-background-position">
     use properties::longhands::{background_position_x, background_position_y};

components/style/properties/shorthands/box.mako.rs

@@ -6,6 +6,7 @@
 
 <%helpers:shorthand
     name="overflow"
+    flags="SHORTHAND_IN_GETCS"
     sub_properties="overflow-x overflow-y"
     spec="https://drafts.csswg.org/css-overflow/#propdef-overflow"
 >

components/style/properties/shorthands/font.mako.rs

@@ -285,6 +285,7 @@
 </%helpers:shorthand>
 
 <%helpers:shorthand name="font-variant"
+                    flags="SHORTHAND_IN_GETCS"
                     sub_properties="font-variant-caps
                                     ${'font-variant-alternates' if product == 'gecko' else ''}
                                     ${'font-variant-east-asian' if product == 'gecko' else ''}

components/style/properties/shorthands/svg.mako.rs

@@ -5,6 +5,7 @@
 <%namespace name="helpers" file="/helpers.mako.rs" />
 
 <%helpers:shorthand name="mask" products="gecko" extra_prefixes="webkit"
+                    flags="SHORTHAND_IN_GETCS"
                     sub_properties="mask-mode mask-repeat mask-clip mask-origin mask-composite mask-position-x
                                     mask-position-y mask-size mask-image"
                     spec="https://drafts.fxtf.org/css-masking/#propdef-mask">
@@ -182,6 +183,7 @@
 </%helpers:shorthand>
 
 <%helpers:shorthand name="mask-position" products="gecko" extra_prefixes="webkit"
+                    flags="SHORTHAND_IN_GETCS"
                     sub_properties="mask-position-x mask-position-y"
                     spec="https://drafts.csswg.org/css-masks-4/#the-mask-position">
     use properties::longhands::{mask_position_x,mask_position_y};

components/style/properties/shorthands/text.mako.rs

@@ -5,6 +5,7 @@
 <%namespace name="helpers" file="/helpers.mako.rs" />
 
 <%helpers:shorthand name="text-decoration"
+                    flags="SHORTHAND_IN_GETCS"
                     sub_properties="text-decoration-line
                     ${' text-decoration-style text-decoration-color' if product == 'gecko' else ''}"
                     spec="https://drafts.csswg.org/css-text-decor/#propdef-text-decoration">