Modernize and trim down SkOnce.

include/gpu/GrResourceKey.h

Index: include/gpu/GrResourceKey.h
diff --git a/include/gpu/GrResourceKey.h b/include/gpu/GrResourceKey.h
index ff83a43104489c3c39878afa63502b4bfde3bcc9..9f8063d955d9945b2dfc88c01bbed127f6b770da 100644
--- a/include/gpu/GrResourceKey.h
+++ b/include/gpu/GrResourceKey.h
@@ -71,7 +71,7 @@ protected:
 
     /** size of the key data, excluding meta-data (hash, domain, etc).  */
     size_t dataSize() const { return this->size() - 4 * kMetaDataCnt; }
- 
+
     /** ptr to the key data, excluding meta-data (hash, domain, etc).  */
     const uint32_t* data() const {
         this->validate();
@@ -290,12 +290,12 @@ private:
  */
 
 /** Place outside of function/class definitions. */
-#define GR_DECLARE_STATIC_UNIQUE_KEY(name) SK_DECLARE_STATIC_ONCE(name##_once)
+#define GR_DECLARE_STATIC_UNIQUE_KEY(name) static SkOnce name##_once
 
 /** Place inside function where the key is used. */
 #define GR_DEFINE_STATIC_UNIQUE_KEY(name)                                                       \
     static SkAlignedSTStorage<1, GrUniqueKey> name##_storage;                                   \
-    SkOnce(&name##_once, gr_init_static_unique_key_once, &name##_storage);                      \
+    name##_once(gr_init_static_unique_key_once, &name##_storage);                               \
     static const GrUniqueKey& name = *reinterpret_cast<GrUniqueKey*>(name##_storage.get());
 
 static inline void gr_init_static_unique_key_once(SkAlignedSTStorage<1,GrUniqueKey>* keyStorage) {