SkTHash: hash from fnptr to functor type

dm/DM.cpp

Index: dm/DM.cpp
diff --git a/dm/DM.cpp b/dm/DM.cpp
index 4b32d2fc1a9549eb20d23f8eb2a2113ac8f339da..ccff84c906710ab4d9185c8feb3ebf82b818cf82 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -144,7 +144,11 @@ struct Gold : public SkString {
         this->append(name);
         this->append(md5);
     }
-    static uint32_t Hash(const Gold& g) { return SkGoodHash((const SkString&)g); }
+    struct Hash {
+        uint32_t operator()(const Gold& g) const {
+            return SkGoodHash()((const SkString&)g);
+        }
+    };
 };
 static SkTHashSet<Gold, Gold::Hash> gGold;