Add Lua SkXfermode skp scraping support

src/utils/debugger/SkDebugCanvas.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkClipStack.h"
 #include "SkColorPriv.h"
 #include "SkDebugCanvas.h"
@@ skipping 36 matching lines @@
         ++idx;
         SkASSERT(idx < (int)SK_ARRAY_COUNT(gTable));
 
         return gTable[idx];
     }
 
     Factory getFactory() const override { return nullptr; }
 #ifndef SK_IGNORE_TO_STRING
     void toString(SkString* str) const override { str->set("OverdrawXfermode"); }
 #endif
+
+protected:
+    void luaGetName(SkString* name) const override { name->set("Overdraw"); }
 };
 
 class DebugPaintFilterCanvas : public SkPaintFilterCanvas {
 public:
     DebugPaintFilterCanvas(int width,
                            int height,
                            bool overdrawViz,
                            bool overrideFilterQuality,
                            SkFilterQuality quality)
         : INHERITED(width, height)
@@ skipping 594 matching lines @@
 }
 
 bool SkDebugCanvas::lastClipStackData(const SkPath& devPath) {
     if (fCalledAddStackData) {
         fClipStackData.appendf("<br>");
         addPathData(devPath, "pathOut");
         return true;
     }
     return false;
 }