diff --git a/dom/canvas/CanvasRenderingContext2D.cpp b/dom/canvas/CanvasRenderingContext2D.cpp
index f9516e82a707..9a41f651cc8a 100644
--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -2901,9 +2901,7 @@ GetFontStyleForServo(Element* aElement, const nsAString& aFont,
   // parsed (including having line-height removed).  (Older drafts of
   // the spec required font sizes be converted to pixels, but that no
   // longer seems to be required.)
-  Servo_DeclarationBlock_SerializeOneValue(declarations,
-                                           eCSSProperty_font,
-                                           &aOutUsedFont);
+  Servo_SerializeFontValueForCanvas(declarations, &aOutUsedFont);
 
   return sc.forget();
 }
diff --git a/layout/style/ServoBindingList.h b/layout/style/ServoBindingList.h
index 1d1c7e116330..985e90f7a0fa 100644
--- a/layout/style/ServoBindingList.h
+++ b/layout/style/ServoBindingList.h
@@ -473,6 +473,11 @@ SERVO_BINDING_FUNC(Servo_StyleSet_GetBaseComputedValuesForElement,
                    const mozilla::ServoElementSnapshotTable* snapshots,
                    mozilla::CSSPseudoElementType pseudo_type)
 
+// For canvas font.
+SERVO_BINDING_FUNC(Servo_SerializeFontValueForCanvas, void,
+                   RawServoDeclarationBlockBorrowed declarations,
+                   nsAString* buffer)
+
 // Style-struct management.
 #define STYLE_STRUCT(name, checkdata_cb)                            \
   struct nsStyle##name;                                             \