Move inline stylesheet parsing out of HTML parser.

Instead, use shared code to parse stylesheet content when it is inserted,
whether during parsing or dynamically by script.

Based on work by sanools in #1350.

src/components/script/dom/node.rs

@@ -6,7 +6,7 @@
 
 use dom::attr::Attr;
 use dom::bindings::codegen::InheritTypes::{CommentCast, DocumentCast, DocumentTypeCast};
-use dom::bindings::codegen::InheritTypes::{ElementCast, TextCast, NodeCast};
+use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLStyleElementCast, TextCast, NodeCast};
 use dom::bindings::codegen::InheritTypes::{CharacterDataCast, NodeBase, NodeDerived};
 use dom::bindings::codegen::InheritTypes::{ProcessingInstructionCast, EventTargetCast};
 use dom::bindings::codegen::NodeBinding::NodeConstants;
@@ -21,6 +21,7 @@ use dom::documentfragment::DocumentFragment;
 use dom::documenttype::DocumentType;
 use dom::element::{Element, ElementTypeId, HTMLAnchorElementTypeId};
 use dom::eventtarget::{EventTarget, NodeTargetTypeId};
+use dom::htmlstyleelement::StyleElementHelpers;
 use dom::nodelist::{NodeList};
 use dom::processinginstruction::ProcessingInstruction;
 use dom::text::Text;
@@ -269,6 +270,8 @@ pub trait NodeHelpers {
     fn add_child(&mut self, new_child: &mut JS<Node>, before: Option<JS<Node>>);
     fn remove_child(&mut self, child: &mut JS<Node>);
 
+    fn child_inserted(&self);
+
     fn get_hover_state(&self) -> bool;
     fn set_hover_state(&mut self, state: bool);
 
@@ -408,6 +411,7 @@ impl NodeHelpers for JS<Node> {
             }
         }
 
+        self.parent_node().map(|parent| parent.child_inserted());
         document.get().content_changed();
     }
 
@@ -499,6 +503,15 @@ impl NodeHelpers for JS<Node> {
         child_node.set_parent_node(None);
     }
 
+    fn child_inserted(&self) {
+        // Parse text content added to an inline stylesheet.
+        match HTMLStyleElementCast::to(self) {
+            Some(elem) => elem.parse_own_css(),
+            None => ()
+        }
+    }
+
+
     fn get_hover_state(&self) -> bool {
         self.get().flags.get_in_hover_state()
     }