diff --git a/dom/canvas/CanvasRenderingContext2D.cpp b/dom/canvas/CanvasRenderingContext2D.cpp
index d29543d1a2c..3b6f9d5893a 100644
--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -3496,22 +3496,6 @@ CanvasRenderingContext2D::DrawDirectlyToCanvas(
   NS_ENSURE_SUCCESS_VOID(rv);
 }
 
-static bool
-IsStandardCompositeOp(CompositionOp op)
-{
-    return (op == CompositionOp::OP_SOURCE ||
-            op == CompositionOp::OP_ATOP ||
-            op == CompositionOp::OP_IN ||
-            op == CompositionOp::OP_OUT ||
-            op == CompositionOp::OP_OVER ||
-            op == CompositionOp::OP_DEST_IN ||
-            op == CompositionOp::OP_DEST_OUT ||
-            op == CompositionOp::OP_DEST_OVER ||
-            op == CompositionOp::OP_DEST_ATOP ||
-            op == CompositionOp::OP_ADD ||
-            op == CompositionOp::OP_XOR);
-}
-
 void
 CanvasRenderingContext2D::SetGlobalCompositeOperation(const nsAString& op,
                                                       ErrorResult& error)
@@ -3551,10 +3535,6 @@ CanvasRenderingContext2D::SetGlobalCompositeOperation(const nsAString& op,
   // XXX ERRMSG we need to report an error to developers here! (bug 329026)
   else return;
 
-  if (!IsStandardCompositeOp(comp_op)) {
-    Demote();
-  }
-
 #undef CANVAS_OP_TO_GFX_OP
   CurrentState().op = comp_op;
 }
@@ -3599,10 +3579,6 @@ CanvasRenderingContext2D::GetGlobalCompositeOperation(nsAString& op,
     error.Throw(NS_ERROR_FAILURE);
   }
 
-  if (!IsStandardCompositeOp(comp_op)) {
-    Demote();
-  }
-
 #undef CANVAS_OP_TO_GFX_OP
 }