style: Use cbindgen for URIs.

This doesn't clean up as much as a whole, but it's a step in the right
direction. In particular, it allows us to start using simple bindings for:

 * Filters
 * Shapes and images, almost. Need to:
   * Get rid of the complex -moz- gradient parsing (let
     layout.css.simple-moz-gradient.enabled get to release).
 * Counters, almost. Need to:
   * Share the Attr representation with Gecko, by not using Option<>.
     * Just another variant should be enough (ContentItem::{Attr,Prefixedattr},
       maybe).

Which in turn allows us to remove a whole lot of bindings in followups to this.

The setup changes a bit. This also removes the double pointer I complained about
while reviewing the shared UA sheet patches. The old setup is:

```
SpecifiedUrl
 * CssUrl
   * Arc<CssUrlData>
     * String
     * UrlExtraData
 * UrlValueSource
   * Arc<CssUrlData>
   * load id
   * resolved uri
   * CORS mode.
   * ...
```

The new one removes the double reference to the url data via URLValue, and looks
like:

```
SpecifiedUrl
 * CssUrl
   * Arc<CssUrlData>
     * String
     * UrlExtraData
     * CorsMode
     * LoadData
       * load id
       * resolved URI
```

The LoadData is the only mutable bit that C++ can change, and is not used from
Rust. Ideally, in the future, we could just use rust-url to resolve the URL
after parsing or something, and make it all immutable. Maybe.

I've verified that this approach still works with the UA sheet patches (via the
LoadDataSource::Lazy).

The reordering of mWillChange is to avoid nsStyleDisplay from going over the
size limit. We want to split it up anyway in bug 1552587, but mBinding gains a
tag member, which means that we were having a bit of extra padding.

One thing I want to explore is to see if we can abuse rustc's non-zero
optimizations to predict the layout from C++, but that's something to explore at
some other point in time and with a lot of care and help from Michael (who sits
next to me and works on rustc ;)).

Differential Revision: https://phabricator.services.mozilla.com/D31742

components/style/properties/gecko.mako.rs

@@ -278,7 +278,7 @@ impl ComputedValuesInner {
 
     #[allow(non_snake_case)]
     pub fn has_moz_binding(&self) -> bool {
-        !self.get_box().gecko.mBinding.mRawPtr.is_null()
+        !self.get_box().gecko.mBinding.is_none()
     }
 }
 
@@ -550,7 +550,7 @@ def set_gecko_property(ffi_name, expr):
                 unsafe {
                     bindings::Gecko_nsStyleSVGPaint_SetURLValue(
                         paint,
-                        url.url_value_ptr(),
+                        &url
                     )
                 }
             }
@@ -591,7 +591,6 @@ def set_gecko_property(ffi_name, expr):
 
     #[allow(non_snake_case)]
     pub fn clone_${ident}(&self) -> longhands::${ident}::computed_value::T {
-        use crate::values::computed::url::ComputedUrl;
         use crate::values::generics::svg::{SVGPaint, SVGPaintKind};
         use self::structs::nsStyleSVGPaintType;
         use self::structs::nsStyleSVGFallbackType;
@@ -613,8 +612,7 @@ def set_gecko_property(ffi_name, expr):
             nsStyleSVGPaintType::eStyleSVGPaintType_ContextStroke => SVGPaintKind::ContextStroke,
             nsStyleSVGPaintType::eStyleSVGPaintType_Server => {
                 SVGPaintKind::PaintServer(unsafe {
-                    let url = RefPtr::new(*paint.mPaint.mPaintServer.as_ref());
-                    ComputedUrl::from_url_value(url)
+                    paint.mPaint.mPaintServer.as_ref().clone()
                 })
             }
             nsStyleSVGPaintType::eStyleSVGPaintType_Color => {
@@ -735,45 +733,6 @@ def set_gecko_property(ffi_name, expr):
     }
 </%def>
 
-<%def name="impl_css_url(ident, gecko_ffi_name)">
-    #[allow(non_snake_case)]
-    pub fn set_${ident}(&mut self, v: longhands::${ident}::computed_value::T) {
-        match v {
-            UrlOrNone::Url(ref url) => {
-                self.gecko.${gecko_ffi_name}.set_move(url.clone_url_value())
-            }
-            UrlOrNone::None => {
-                unsafe {
-                    self.gecko.${gecko_ffi_name}.clear();
-                }
-            }
-        }
-    }
-    #[allow(non_snake_case)]
-    pub fn copy_${ident}_from(&mut self, other: &Self) {
-        unsafe {
-            self.gecko.${gecko_ffi_name}.set(&other.gecko.${gecko_ffi_name});
-        }
-    }
-    #[allow(non_snake_case)]
-    pub fn reset_${ident}(&mut self, other: &Self) {
-        self.copy_${ident}_from(other)
-    }
-
-    #[allow(non_snake_case)]
-    pub fn clone_${ident}(&self) -> longhands::${ident}::computed_value::T {
-        use crate::values::computed::url::ComputedUrl;
-
-        if self.gecko.${gecko_ffi_name}.mRawPtr.is_null() {
-            return UrlOrNone::none()
-        }
-
-        UrlOrNone::Url(unsafe {
-            ComputedUrl::from_url_value(self.gecko.${gecko_ffi_name}.to_safe())
-        })
-    }
-</%def>
-
 <%def name="impl_logical(name, **kwargs)">
     ${helpers.logical_setter(name)}
 </%def>
@@ -879,7 +838,6 @@ impl Clone for ${style_struct.gecko_struct_name} {
         "SVGOpacity": impl_svg_opacity,
         "SVGPaint": impl_svg_paint,
         "SVGWidth": impl_svg_length,
-        "url::UrlOrNone": impl_css_url,
     }
 
     def longhand_method(longhand):
@@ -2164,8 +2122,7 @@ fn static_assert() {
                           animation-iteration-count animation-timing-function
                           clear transition-duration transition-delay
                           transition-timing-function transition-property
-                          transform-style -moz-binding shape-outside
-                          -webkit-line-clamp""" %>
+                          transform-style shape-outside -webkit-line-clamp""" %>
 <%self:impl_trait style_struct_name="Box" skip_longhands="${skip_box_longhands}">
     #[inline]
     pub fn set_display(&mut self, v: longhands::display::computed_value::T) {
@@ -2205,7 +2162,6 @@ fn static_assert() {
         gecko_inexhaustive=True,
     ) %>
     ${impl_keyword('clear', 'mBreakType', clear_keyword)}
-    ${impl_css_url('_moz_binding', 'mBinding')}
     ${impl_transition_time_value('delay', 'Delay')}
     ${impl_transition_time_value('duration', 'Duration')}
     ${impl_transition_timing_function()}
@@ -2834,10 +2790,7 @@ fn static_assert() {
             }
             UrlOrNone::Url(ref url) => {
                 unsafe {
-                    Gecko_SetListStyleImageImageValue(
-                        &mut *self.gecko,
-                        url.url_value_ptr(),
-                    );
+                    Gecko_SetListStyleImageImageValue(&mut *self.gecko, url);
                 }
             }
         }
@@ -3145,7 +3098,7 @@ fn static_assert() {
                 },
                 Url(ref url) => {
                     unsafe {
-                        bindings::Gecko_nsStyleFilter_SetURLValue(gecko_filter, url.url_value_ptr());
+                        bindings::Gecko_nsStyleFilter_SetURLValue(gecko_filter, url);
                     }
                 },
             }
@@ -3164,7 +3117,6 @@ fn static_assert() {
 
     pub fn clone_filter(&self) -> longhands::filter::computed_value::T {
         use crate::values::generics::effects::Filter;
-        use crate::values::computed::url::ComputedUrl;
         use crate::gecko_bindings::structs::NS_STYLE_FILTER_BLUR;
         use crate::gecko_bindings::structs::NS_STYLE_FILTER_BRIGHTNESS;
         use crate::gecko_bindings::structs::NS_STYLE_FILTER_CONTRAST;
@@ -3205,8 +3157,7 @@ fn static_assert() {
                 },
                 NS_STYLE_FILTER_URL => {
                     Filter::Url(unsafe {
-                        let url = RefPtr::new(*filter.__bindgen_anon_1.mURL.as_ref());
-                        ComputedUrl::from_url_value(url)
+                        filter.__bindgen_anon_1.mURL.as_ref().clone()
                     })
                 }
                 _ => unreachable!("Unknown filter function?"),
@@ -3550,7 +3501,7 @@ clip-path
             unsafe {
                 Gecko_SetCursorImageValue(
                     &mut self.gecko.mCursorImages[i],
-                    v.images[i].url.url_value_ptr(),
+                    &v.images[i].url
                 );
             }
 
@@ -3769,7 +3720,7 @@ clip-path
                             unsafe {
                                 bindings::Gecko_SetContentDataImageValue(
                                     &mut self.gecko.mContents[i],
-                                    url.url_value_ptr(),
+                                    url,
                                 )
                             }
                         }

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

@@ -644,7 +644,6 @@ ${helpers.predefined_type(
     "basic_shape::FloatAreaShape",
     "generics::basic_shape::ShapeSource::None",
     products="gecko",
-    boxed=True,
     animation_value_type="basic_shape::FloatAreaShape",
     flags="APPLIES_TO_FIRST_LETTER",
     spec="https://drafts.csswg.org/css-shapes/#shape-outside-property",