style: Kill SharedStyleContext::default_computed_values.

Now that cascade() gets a Device, we can use the default computed values from
there to avoid propagating that state all over the place.

Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>

components/layout/construct.rs

@@ -662,8 +662,8 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
             if node_is_input_or_text_area {
                 style = self.style_context()
                             .stylist
-                            .style_for_anonymous_box(&PseudoElement::ServoInputText, &style,
+                            .style_for_anonymous_box(&PseudoElement::ServoInputText,
-                                                     &self.style_context().default_computed_values)
+                                                     &style)
             }
 
             self.create_fragments_for_node_text_content(&mut initial_fragments, node, &style)
@@ -1100,7 +1100,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         let wrapper_style = self.style_context()
                                 .stylist
                                 .style_for_anonymous_box(&PseudoElement::ServoTableWrapper,
-                                                         &table_style, &self.style_context().default_computed_values);
+                                                         &table_style);
         let wrapper_fragment =
             Fragment::from_opaque_node_and_style(node.opaque(),
                                                  PseudoElementType::Normal,
@@ -2080,7 +2080,8 @@ impl Legalizer {
         let reference_block = reference.as_block();
         let mut new_style = reference_block.fragment.style.clone();
         for pseudo in pseudos {
-            new_style = context.stylist.style_for_anonymous_box(pseudo, &new_style, &context.default_computed_values)
+            new_style = context.stylist.style_for_anonymous_box(pseudo,
+                                                                &new_style)
         }
         let fragment = reference_block.fragment
                                       .create_similar_anonymous_fragment(new_style,

components/layout_thread/lib.rs

@@ -114,7 +114,6 @@ use style::error_reporting::{ParseErrorReporter, StdoutErrorReporter};
 use style::logical_geometry::LogicalPoint;
 use style::media_queries::{Device, MediaType};
 use style::parser::ParserContextExtraData;
-use style::properties::ComputedValues;
 use style::servo::restyle_damage::{REFLOW, REFLOW_OUT_OF_FLOW, REPAINT, REPOSITION, STORE_OVERFLOW};
 use style::stylesheets::{Origin, Stylesheet, UserAgentStylesheets};
 use style::stylist::Stylist;
@@ -510,11 +509,6 @@ impl LayoutThread {
                 local_context_creation_data: Mutex::new(thread_local_style_context_creation_data),
                 timer: self.timer.clone(),
                 quirks_mode: self.quirks_mode.unwrap(),
-                // FIXME(bz): This isn't really right, but it's no more wrong
-                // than what we used to do.  See
-                // https://github.com/servo/servo/issues/14773 for fixing it
-                // properly.
-                default_computed_values: Arc::new(ComputedValues::initial_values().clone()),
             },
             image_cache_thread: Mutex::new(self.image_cache_thread.clone()),
             font_cache_thread: Mutex::new(self.font_cache_thread.clone()),

components/script_layout_interface/wrapper_traits.rs

@@ -407,7 +407,6 @@ pub trait ThreadSafeLayoutElement: Clone + Copy + Sized + Debug +
                                 context.stylist.precomputed_values_for_pseudo(
                                     &style_pseudo,
                                     Some(data.styles().primary.values()),
-                                    &context.default_computed_values,
                                     CascadeFlags::empty());
                             data.styles_mut().pseudos
                                 .insert(style_pseudo.clone(), new_style);
@@ -424,8 +423,7 @@ pub trait ThreadSafeLayoutElement: Clone + Copy + Sized + Debug +
                                        .lazily_compute_pseudo_element_style(
                                            unsafe { &self.unsafe_get() },
                                            &style_pseudo,
-                                           data.styles().primary.values(),
+                                           data.styles().primary.values());
-                                           &context.default_computed_values);
                             data.styles_mut().pseudos
                                 .insert(style_pseudo.clone(), new_style.unwrap());
                         }

components/style/animation.rs

@@ -431,7 +431,6 @@ fn compute_style_for_animation_step(context: &SharedStyleContext,
                                                iter,
                                                previous_style,
                                                previous_style,
-                                               &context.default_computed_values,
                                                /* cascade_info = */ None,
                                                context.error_reporter.clone(),
                                                /* Metrics provider */ None,

components/style/context.rs

@@ -14,7 +14,6 @@ use error_reporting::ParseErrorReporter;
 use euclid::Size2D;
 use matching::StyleSharingCandidateCache;
 use parking_lot::RwLock;
-use properties::ComputedValues;
 use selector_parser::PseudoElement;
 use selectors::matching::ElementSelectorFlags;
 use servo_config::opts;
@@ -84,10 +83,6 @@ pub struct SharedStyleContext {
 
     /// The QuirksMode state which the document needs to be rendered with
     pub quirks_mode: QuirksMode,
-
-    /// The default computed values to use for elements with no rules
-    /// applying to them.
-    pub default_computed_values: Arc<ComputedValues>,
 }
 
 impl SharedStyleContext {

components/style/gecko/data.rs

@@ -103,7 +103,7 @@ impl PerDocumentStyleDataImpl {
 
     /// Get the default computed values for this document.
     pub fn default_computed_values(&self) -> &Arc<ComputedValues> {
-        self.stylist.device.default_values_arc()
+        self.stylist.device.default_computed_values_arc()
     }
 }
 

components/style/gecko/media_queries.rs

@@ -54,10 +54,16 @@ impl Device {
 
     /// Returns the default computed values as a reference, in order to match
     /// Servo.
-    pub fn default_values(&self) -> &ComputedValues {
+    pub fn default_computed_values(&self) -> &ComputedValues {
         &*self.default_values
     }
 
+    /// Returns the default computed values, but wrapped in an arc for cheap
+    /// cloning.
+    pub fn default_computed_values_arc(&self) -> &Arc<ComputedValues> {
+        &self.default_values
+    }
+
     /// Returns the default computed values as an `Arc`, in order to avoid
     /// clones.
     pub fn default_values_arc(&self) -> &Arc<ComputedValues> {
@@ -491,7 +497,7 @@ impl Expression {
                       self.feature.mRangeType == nsMediaFeature_RangeType::eMinMaxAllowed,
                       "Whoops, wrong range");
 
-        let default_values = device.default_values();
+        let default_values = device.default_computed_values();
 
         // http://dev.w3.org/csswg/mediaqueries3/#units
         // em units are relative to the initial font-size.

components/style/matching.rs

@@ -543,7 +543,6 @@ trait PrivateMatchMethods: TElement {
                              rule_node,
                              inherited_values,
                              layout_parent_style,
-                             &shared_context.default_computed_values,
                              Some(&mut cascade_info),
                              shared_context.error_reporter.clone(),
                              cascade_flags));

components/style/properties/gecko.mako.rs

@@ -83,7 +83,7 @@ pub struct ComputedValues {
 }
 
 impl ComputedValues {
-    pub fn inherit_from(parent: &Arc<Self>, default: &Arc<Self>) -> Arc<Self> {
+    pub fn inherit_from(parent: &Self, default: &Self) -> Arc<Self> {
         Arc::new(ComputedValues {
             custom_properties: parent.custom_properties.clone(),
             shareable: parent.shareable,

components/style/properties/properties.mako.rs

@@ -1807,16 +1807,24 @@ pub fn cascade(device: &Device,
                rule_node: &StrongRuleNode,
                parent_style: Option<<&ComputedValues>,
                layout_parent_style: Option<<&ComputedValues>,
-               default_style: &ComputedValues,
                cascade_info: Option<<&mut CascadeInfo>,
                error_reporter: StdBox<ParseErrorReporter + Send>,
                flags: CascadeFlags)
                -> ComputedValues {
     debug_assert_eq!(parent_style.is_some(), layout_parent_style.is_some());
     let (is_root_element, inherited_style, layout_parent_style) = match parent_style {
-        Some(parent_style) => (false, parent_style, layout_parent_style.unwrap()),
+        Some(parent_style) => {
-        None => (true, &*default_style, &*default_style),
+            (false,
+             parent_style,
+             layout_parent_style.unwrap())
+        },
+        None => {
+            (true,
+             device.default_computed_values(),
+             device.default_computed_values())
+        }
     };
+
     // Hold locks until after the apply_declarations() call returns.
     // Use filter_map because the root node has no style source.
     let lock_guards = rule_node.self_and_ancestors().filter_map(|node| {
@@ -1841,7 +1849,6 @@ pub fn cascade(device: &Device,
                        iter_declarations,
                        inherited_style,
                        layout_parent_style,
-                       default_style,
                        cascade_info,
                        error_reporter,
                        None,
@@ -1855,7 +1862,6 @@ pub fn apply_declarations<'a, F, I>(device: &Device,
                                     iter_declarations: F,
                                     inherited_style: &ComputedValues,
                                     layout_parent_style: &ComputedValues,
-                                    default_style: &ComputedValues,
                                     mut cascade_info: Option<<&mut CascadeInfo>,
                                     mut error_reporter: StdBox<ParseErrorReporter + Send>,
                                     font_metrics_provider: Option<<&FontMetricsProvider>,
@@ -1864,6 +1870,7 @@ pub fn apply_declarations<'a, F, I>(device: &Device,
     where F: Fn() -> I,
           I: Iterator<Item = &'a PropertyDeclaration>,
 {
+    let default_style = device.default_computed_values();
     let inherited_custom_properties = inherited_style.custom_properties();
     let mut custom_properties = None;
     let mut seen_custom = HashSet::new();

components/style/servo/media_queries.rs

@@ -39,7 +39,10 @@ impl Device {
     }
 
     /// Return the default computed values for this device.
-    pub fn default_values(&self) -> &ComputedValues {
+    pub fn default_computed_values(&self) -> &ComputedValues {
+        // FIXME(bz): This isn't really right, but it's no more wrong
+        // than what we used to do.  See
+        // https://github.com/servo/servo/issues/14773 for fixing it properly.
         ComputedValues::initial_values()
     }
 
@@ -171,7 +174,7 @@ pub enum Range<T> {
 
 impl Range<specified::Length> {
     fn to_computed_range(&self, device: &Device) -> Range<Au> {
-        let default_values = device.default_values();
+        let default_values = device.default_computed_values();
         // http://dev.w3.org/csswg/mediaqueries3/#units
         // em units are relative to the initial font-size.
         let context = computed::Context {

components/style/stylist.rs

@@ -295,7 +295,6 @@ impl Stylist {
     pub fn precomputed_values_for_pseudo(&self,
                                          pseudo: &PseudoElement,
                                          parent: Option<&Arc<ComputedValues>>,
-                                         default: &ComputedValues,
                                          cascade_flags: CascadeFlags)
                                          -> ComputedStyle {
         debug_assert!(SelectorImpl::pseudo_element_cascade_type(pseudo).is_precomputed());
@@ -329,7 +328,6 @@ impl Stylist {
                                 &rule_node,
                                 parent.map(|p| &**p),
                                 parent.map(|p| &**p),
-                                default,
                                 None,
                                 Box::new(StdoutErrorReporter),
                                 cascade_flags);
@@ -340,8 +338,7 @@ impl Stylist {
     #[cfg(feature = "servo")]
     pub fn style_for_anonymous_box(&self,
                                    pseudo: &PseudoElement,
-                                   parent_style: &Arc<ComputedValues>,
+                                   parent_style: &Arc<ComputedValues>)
-                                   default_style: &ComputedValues)
                                    -> Arc<ComputedValues> {
         // For most (but not all) pseudo-elements, we inherit all values from the parent.
         let inherit_all = match *pseudo {
@@ -364,7 +361,7 @@ impl Stylist {
         if inherit_all {
             cascade_flags.insert(INHERIT_ALL);
         }
-        self.precomputed_values_for_pseudo(&pseudo, Some(parent_style), default_style, cascade_flags)
+        self.precomputed_values_for_pseudo(&pseudo, Some(parent_style), cascade_flags)
             .values.unwrap()
     }
 
@@ -378,8 +375,7 @@ impl Stylist {
     pub fn lazily_compute_pseudo_element_style<E>(&self,
                                                   element: &E,
                                                   pseudo: &PseudoElement,
-                                                  parent: &Arc<ComputedValues>,
+                                                  parent: &Arc<ComputedValues>)
-                                                  default: &Arc<ComputedValues>)
                                                   -> Option<ComputedStyle>
         where E: TElement +
                  fmt::Debug +
@@ -414,7 +410,6 @@ impl Stylist {
                                 &rule_node,
                                 Some(&**parent),
                                 Some(&**parent),
-                                default,
                                 None,
                                 Box::new(StdoutErrorReporter),
                                 CascadeFlags::empty());

components/style/viewport.rs

@@ -688,9 +688,9 @@ impl MaybeNew for ViewportConstraints {
         let context = Context {
             is_root_element: false,
             device: device,
-            inherited_style: device.default_values(),
+            inherited_style: device.default_computed_values(),
-            layout_parent_style: device.default_values(),
+            layout_parent_style: device.default_computed_values(),
-            style: device.default_values().clone(),
+            style: device.default_computed_values().clone(),
             font_metrics_provider: None, // TODO: Should have!
         };
 

ports/geckolib/glue.rs

@@ -171,7 +171,6 @@ fn create_shared_context(per_doc_data: &PerDocumentStyleDataImpl) -> SharedStyle
         timer: Timer::new(),
         // FIXME Find the real QuirksMode information for this document
         quirks_mode: QuirksMode::NoQuirks,
-        default_computed_values: per_doc_data.default_computed_values().clone(),
     }
 }
 
@@ -634,7 +633,6 @@ pub extern "C" fn Servo_ComputedValues_GetForAnonymousBox(parent_style_or_null:
         cascade_flags.insert(SKIP_ROOT_AND_ITEM_BASED_DISPLAY_FIXUP);
     }
     data.stylist.precomputed_values_for_pseudo(&pseudo, maybe_parent,
-                                               data.default_computed_values(),
                                                cascade_flags)
         .values.unwrap()
         .into_strong()
@@ -680,8 +678,7 @@ fn get_pseudo_style(element: GeckoElement, pseudo_tag: *mut nsIAtom,
             let base = styles.primary.values();
             d.stylist.lazily_compute_pseudo_element_style(&element,
                                                           &pseudo,
-                                                          base,
+                                                          base)
-                                                          &d.default_computed_values())
                      .map(|s| s.values().clone())
         },
     }
@@ -1438,7 +1435,7 @@ pub extern "C" fn Servo_GetComputedKeyframeValues(keyframes: RawGeckoKeyframeLis
     let style = ComputedValues::as_arc(&style);
     let parent_style = parent_style.as_ref().map(|r| &**ComputedValues::as_arc(&r));
 
-    let default_values = data.stylist.device.default_values();
+    let default_values = data.default_computed_values();
 
     let context = Context {
         is_root_element: false,