--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -2327,17 +2327,17 @@ nsWindow::UpdateAlpha(SourceSurface* aSo
     // We need to create our own buffer to force the stride to match the
     // expected stride.
     int32_t stride = GetAlignedStride<4>(BytesPerPixel(SurfaceFormat::A8) *
                                          aBoundsRect.width);
     int32_t bufferSize = stride * aBoundsRect.height;
     auto imageBuffer = MakeUniqueFallible<uint8_t[]>(bufferSize);
     {
         RefPtr<DrawTarget> drawTarget = gfxPlatform::GetPlatform()->
-            CreateDrawTargetForData(imageBuffer, aBoundsRect.Size(),
+            CreateDrawTargetForData(imageBuffer.get(), aBoundsRect.Size(),
                                     stride, SurfaceFormat::A8);
 
         if (drawTarget) {
             drawTarget->DrawSurface(aSourceSurface, Rect(aBoundsRect.x, aBoundsRect.y, aBoundsRect.width, aBoundsRect.height),
                                     Rect(0, 0, aSourceSurface->GetSize().width, aSourceSurface->GetSize().height),
                                     DrawSurfaceOptions(Filter::POINT), DrawOptions(1.0f, CompositionOp::OP_SOURCE));
         }
     }