diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index 9536d0aea0fc..2386d645d7b4 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -53,6 +53,7 @@
 #include "nsContentUtils.h"
 #include "nsPrintfCString.h"
 #include "UnitTransforms.h"
+#include "LayersLogging.h"
 
 #include <stdint.h>
 #include <algorithm>
@@ -5205,6 +5206,16 @@ bool nsDisplayTransform::UntransformVisibleRect(nsDisplayListBuilder* aBuilder,
   return true;
 }
 
+#ifdef MOZ_DUMP_PAINTING
+void
+nsDisplayTransform::WriteDebugInfo(nsACString& aTo)
+{
+  gfx::Matrix4x4 transform;
+  gfx::ToMatrix4x4(GetTransform(), transform);
+  AppendToString(aTo, transform);
+}
+#endif
+
 nsDisplaySVGEffects::nsDisplaySVGEffects(nsDisplayListBuilder* aBuilder,
                                          nsIFrame* aFrame, nsDisplayList* aList)
     : nsDisplayWrapList(aBuilder, aFrame, aList),
diff --git a/layout/base/nsDisplayList.h b/layout/base/nsDisplayList.h
index bde946faecfa..90e6ecec49b9 100644
--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -3370,6 +3370,9 @@ public:
 
   virtual bool SetVisibleRegionOnLayer() MOZ_OVERRIDE { return false; }
 
+#ifdef MOZ_DUMP_PAINTING
+  virtual void WriteDebugInfo(nsACString& aTo) MOZ_OVERRIDE;
+#endif
 private:
   static gfx3DMatrix GetResultingTransformMatrixInternal(const FrameTransformProperties& aProperties,
                                                          const nsPoint& aOrigin,