Move the definition of ServoThreadSafeLayoutNode::canvas_data to script.

components/layout/wrapper.rs

@@ -46,7 +46,7 @@ use script::dom::bindings::js::LayoutJS;
 use script::dom::characterdata::LayoutCharacterDataHelpers;
 use script::dom::document::{Document, LayoutDocumentHelpers};
 use script::dom::element::{Element, LayoutElementHelpers, RawLayoutElementHelpers};
-use script::dom::htmlcanvaselement::{LayoutHTMLCanvasElementHelpers, HTMLCanvasData};
+use script::dom::htmlcanvaselement::HTMLCanvasData;
 use script::dom::htmliframeelement::HTMLIFrameElement;
 use script::dom::node::{CAN_BE_FRAGMENTED, HAS_CHANGED, HAS_DIRTY_DESCENDANTS, IS_DIRTY};
 use script::dom::node::{LayoutNodeHelpers, Node, OpaqueStyleAndLayoutData};
@@ -1151,10 +1151,8 @@ impl<'ln> ThreadSafeLayoutNode for ServoThreadSafeLayoutNode<'ln> {
     }
 
     fn canvas_data(&self) -> Option<HTMLCanvasData> {
-        unsafe {
-            let canvas_element = self.get_jsmanaged().downcast();
-            canvas_element.map(|canvas| canvas.data())
-        }
+        let this = unsafe { self.get_jsmanaged() };
+        this.canvas_data()
     }
 
     fn iframe_pipeline_id(&self) -> PipelineId {

components/script/dom/node.rs

@@ -38,6 +38,7 @@ use dom::documenttype::DocumentType;
 use dom::element::{Element, ElementCreator};
 use dom::eventtarget::EventTarget;
 use dom::htmlbodyelement::HTMLBodyElement;
+use dom::htmlcanvaselement::{LayoutHTMLCanvasElementHelpers, HTMLCanvasData};
 use dom::htmlcollection::HTMLCollection;
 use dom::htmlelement::HTMLElement;
 use dom::htmlimageelement::{HTMLImageElement, LayoutHTMLImageElementHelpers};
@@ -965,6 +966,7 @@ pub trait LayoutNodeHelpers {
     fn text_content(&self) -> String;
     fn selection(&self) -> Option<Range<usize>>;
     fn image_url(&self) -> Option<Url>;
+    fn canvas_data(&self) -> Option<HTMLCanvasData>;
 }
 
 impl LayoutNodeHelpers for LayoutJS<Node> {
@@ -1094,6 +1096,11 @@ impl LayoutNodeHelpers for LayoutJS<Node> {
                 .image_url()
         }
     }
+
+    fn canvas_data(&self) -> Option<HTMLCanvasData> {
+        self.downcast()
+            .map(|canvas| canvas.data())
+    }
 }