style: Parse the legacy border attribute per the legacy HTML specification.

Additionally, this patch cleans up some miscellaneous formatting issues
and refactors files in `layout/css/` somewhat to eliminate needless
levels of indirection. It also fixes our handling of presentational
hints that only apply if border is nonzero.

components/script/dom/element.rs

@@ -15,8 +15,10 @@ use dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementMethods;
 use dom::bindings::codegen::Bindings::NamedNodeMapBinding::NamedNodeMapMethods;
-use dom::bindings::codegen::InheritTypes::{ElementDerived, HTMLInputElementDerived, HTMLTableCellElementDerived};
-use dom::bindings::codegen::InheritTypes::{HTMLInputElementCast, NodeCast, EventTargetCast, ElementCast};
+use dom::bindings::codegen::InheritTypes::{ElementCast, ElementDerived, EventTargetCast};
+use dom::bindings::codegen::InheritTypes::{HTMLInputElementCast, HTMLInputElementDerived};
+use dom::bindings::codegen::InheritTypes::{HTMLTableElementCast, HTMLTableElementDerived};
+use dom::bindings::codegen::InheritTypes::{HTMLTableCellElementDerived, NodeCast};
 use dom::bindings::js::{MutNullableJS, JS, JSRef, Temporary, TemporaryPushable};
 use dom::bindings::js::{OptionalRootable, Root};
 use dom::bindings::utils::{Reflectable, Reflector};
@@ -32,14 +34,16 @@ use dom::eventtarget::{EventTarget, NodeTargetTypeId, EventTargetHelpers};
 use dom::htmlcollection::HTMLCollection;
 use dom::htmlinputelement::{HTMLInputElement, RawLayoutHTMLInputElementHelpers};
 use dom::htmlserializer::serialize;
+use dom::htmltableelement::{HTMLTableElement, HTMLTableElementHelpers};
 use dom::htmltablecellelement::{HTMLTableCellElement, HTMLTableCellElementHelpers};
-use dom::node::{CLICK_IN_PROGRESS, ElementNodeTypeId, Node, NodeHelpers, NodeIterator};
-use dom::node::{document_from_node, window_from_node, LayoutNodeHelpers, NodeStyleDamaged};
-use dom::node::{OtherNodeDamage};
+use dom::node::{CLICK_IN_PROGRESS, ElementNodeTypeId, LayoutNodeHelpers, Node, NodeHelpers};
+use dom::node::{NodeIterator, NodeStyleDamaged, OtherNodeDamage, document_from_node};
+use dom::node::{window_from_node};
 use dom::nodelist::NodeList;
 use dom::virtualmethods::{VirtualMethods, vtable_for};
 use devtools_traits::AttrInfo;
-use style::{IntegerAttribute, LengthAttribute, SizeIntegerAttribute, WidthLengthAttribute};
+use style::{BorderUnsignedIntegerAttribute, IntegerAttribute, LengthAttribute};
+use style::{SizeIntegerAttribute, UnsignedIntegerAttribute, WidthLengthAttribute};
 use style::{matches, parse_selector_list_from_str};
 use style;
 use servo_util::namespace;
@@ -201,6 +205,8 @@ pub trait RawLayoutElementHelpers {
     unsafe fn get_integer_attribute_for_layout(&self, integer_attribute: IntegerAttribute)
                                                -> Option<i32>;
     unsafe fn get_checked_state_for_layout(&self) -> bool;
+    unsafe fn get_unsigned_integer_attribute_for_layout(&self, attribute: UnsignedIntegerAttribute)
+                                                        -> Option<u32>;
     fn local_name<'a>(&'a self) -> &'a Atom;
     fn namespace<'a>(&'a self) -> &'a Namespace;
     fn style_attribute<'a>(&'a self) -> &'a DOMRefCell<Option<style::PropertyDeclarationBlock>>;
@@ -285,11 +291,15 @@ impl RawLayoutElementHelpers for Element {
                                               -> LengthOrPercentageOrAuto {
         match length_attribute {
             WidthLengthAttribute => {
-                if !self.is_htmltablecellelement() {
-                    panic!("I'm not a table cell!")
+                if self.is_htmltableelement() {
+                    let this: &HTMLTableElement = mem::transmute(self);
+                    this.get_width()
+                } else if self.is_htmltablecellelement() {
+                    let this: &HTMLTableCellElement = mem::transmute(self);
+                    this.get_width()
+                } else {
+                    panic!("I'm not a table or table cell!")
                 }
-                let this: &HTMLTableCellElement = mem::transmute(self);
-                this.get_width()
             }
         }
     }
@@ -319,6 +329,26 @@ impl RawLayoutElementHelpers for Element {
         this.get_checked_state_for_layout()
     }
 
+    unsafe fn get_unsigned_integer_attribute_for_layout(&self,
+                                                        attribute: UnsignedIntegerAttribute)
+                                                        -> Option<u32> {
+        match attribute {
+            BorderUnsignedIntegerAttribute => {
+                if self.is_htmltableelement() {
+                    let this: &HTMLTableElement = mem::transmute(self);
+                    this.get_border()
+                } else if self.is_htmltablecellelement() {
+                    let this: &HTMLTableCellElement = mem::transmute(self);
+                    this.get_border()
+                } else {
+                    // Don't panic since `:-servo-nonzero-border` can cause this to be called on
+                    // arbitrary elements.
+                    None
+                }
+            }
+        }
+    }
+
     // Getters used in components/layout/wrapper.rs
 
     fn local_name<'a>(&'a self) -> &'a Atom {
@@ -1222,6 +1252,17 @@ impl<'a> style::TElement<'a> for JSRef<'a, Element> {
             }
         }
     }
+    fn has_nonzero_border(self) -> bool {
+        match HTMLTableElementCast::to_ref(self) {
+            None => false,
+            Some(this) => {
+                match this.get_border() {
+                    None | Some(0) => false,
+                    Some(_) => true,
+                }
+            }
+        }
+    }
 }
 
 pub trait ActivationElementHelpers<'a> {