Add dump_record to make inspecting before/after SkRecordOptimize easy.

tools/dump_record.cpp

Index: tools/dump_record.cpp
diff --git a/tools/dump_record.cpp b/tools/dump_record.cpp
index 4abf77a4d4728245fea095abf67e35e994f42d1f..86911555257dd60f0181a2ae4de42b906f4e0d08 100644
--- a/tools/dump_record.cpp
+++ b/tools/dump_record.cpp
@@ -59,6 +59,8 @@ private:
     #define CASE(U) case SkRecords::U##_Type: return #U;
         switch(T::kType) { SK_RECORD_TYPES(CASE); }
     #undef CASE
+        SkDEBUGFAIL("Unknown T");
+        return "Unknown T";
     }
 
     static const char* NameOf(const SkRecords::SaveLayer&) {