Add empty getter and setter for font attribute

components/script/canvas_state.rs

@@ -1558,6 +1558,16 @@ impl CanvasState {
         ));
         Ok(())
     }
+
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-font
+    pub fn font(&self) -> DOMString {
+        unimplemented!()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-font
+    pub fn set_font(&self, _value: DOMString) {
+        unimplemented!()
+    }
 }
 
 pub fn parse_color(string: &str) -> Result<RGBA, ()> {

components/script/dom/canvasrenderingcontext2d.rs

@@ -606,6 +606,16 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
     fn SetShadowColor(&self, value: DOMString) {
         self.canvas_state.set_shadow_color(value)
     }
+
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-font
+    fn Font(&self) -> DOMString {
+        self.canvas_state.borrow().font()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-font
+    fn SetFont(&self, value: DOMString) {
+        self.canvas_state.borrow().set_font(value)
+    }
 }
 
 impl Drop for CanvasRenderingContext2D {

components/script/dom/offscreencanvasrenderingcontext2d.rs

@@ -513,4 +513,14 @@ impl OffscreenCanvasRenderingContext2DMethods for OffscreenCanvasRenderingContex
         self.canvas_state
             .ellipse(x, y, rx, ry, rotation, start, end, ccw)
     }
+
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-font
+    fn Font(&self) -> DOMString {
+        self.canvas_state.borrow().font()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-font
+    fn SetFont(&self, value: DOMString) {
+        self.canvas_state.borrow().set_font(value)
+    }
 }

components/script/dom/webidls/CanvasRenderingContext2D.webidl

@@ -211,7 +211,7 @@ interface mixin CanvasPathDrawingStyles {
 [Exposed=(PaintWorklet, Window, Worker)]
 interface mixin CanvasTextDrawingStyles {
   // text
-  //attribute DOMString font; // (default 10px sans-serif)
+  attribute DOMString font; // (default 10px sans-serif)
   //attribute CanvasTextAlign textAlign; // "start", "end", "left", "right", "center" (default: "start")
   //attribute CanvasTextBaseline textBaseline; // "top", "hanging", "middle", "alphabetic",
                                       // "ideographic", "bottom" (default: "alphabetic")