--- a/dom/canvas/ImageBitmap.cpp
+++ b/dom/canvas/ImageBitmap.cpp
@@ -863,20 +863,16 @@ ImageBitmap::CreateInternal(nsIGlobalObj
 
   // If the HTMLCanvasElement's rendering context is WebGL, then the snapshot
   // we got from the HTMLCanvasElement is a DataSourceSurface which is a copy
   // of the rendering context. We handle cropping in this case.
   bool needToReportMemoryAllocation = false;
   if ((aCanvasEl.GetCurrentContextType() == CanvasContextType::WebGL1 ||
        aCanvasEl.GetCurrentContextType() == CanvasContextType::WebGL2) &&
       aCropRect.isSome()) {
-    // The _surface_ must be a DataSourceSurface.
-    MOZ_ASSERT(surface->IsDataSourceSurface(),
-               "The snapshot SourceSurface from WebGL rendering contest is not \
-               DataSourceSurface.");
     RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface();
     croppedSurface = CropAndCopyDataSourceSurface(dataSurface, cropRect);
     cropRect.MoveTo(0, 0);
     needToReportMemoryAllocation = true;
   }
   else {
     croppedSurface = surface;
   }