Add Lua SkXfermode skp scraping support

tools/lua/xfer-counter.lua

Index: tools/lua/xfer-counter.lua
diff --git a/tools/lua/xfer-counter.lua b/tools/lua/xfer-counter.lua
new file mode 100644
index 0000000000000000000000000000000000000000..c9d659ceb05f097a1548981d96cf1c2a9a6d35bc
--- /dev/null
+++ b/tools/lua/xfer-counter.lua
@@ -0,0 +1,40 @@
+
+function sk_scrape_startcanvas(c, fileName)
+end
+
+function sk_scrape_endcanvas(c, fileName)
+end
+
+local gXM_Count = 0
+local gXferModeTab = {}
+
+function sk_scrape_accumulate(t)
+    if not t.paint then
+        return
+    end
+
+    local xferMode = t.paint:getXfermode()
+
+    if xferMode then
+        local modeName = xferMode:getTypeName()
+
+        if gXferModeTab[modeName] == nil then
+            gXferModeTab[modeName] = 1;
+        else
+            gXferModeTab[modeName] = gXferModeTab[modeName] + 1
+        end
+        gXM_Count = gXM_Count + 1
+    end
+end
+
+function sk_scrape_summarize()
+    for key,value in pairs(gXferModeTab) do
+        io.write(key, ": ", value, "\n")
+    end
+    io.write("total: ", gXM_Count)
+end
+
+function test_summary()
+    io.write("just testing test_summary\n")
+end
+