Revert of SkOncePtr -> SkOnce

src/core/SkPathRef.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBuffer.h"
-#include "SkOnce.h"
+#include "SkOncePtr.h"
 #include "SkPath.h"
 #include "SkPathRef.h"
 #include <limits>
 
 //////////////////////////////////////////////////////////////////////////////
 SkPathRef::Editor::Editor(SkAutoTUnref<SkPathRef>* pathRef,
                           int incReserveVerbs,
                           int incReservePoints)
 {
     if ((*pathRef)->unique()) {
@@ skipping 18 matching lines @@
 
     SkDEBUGCODE(fPoints = nullptr;)
     SkDEBUGCODE(fVerbs = nullptr;)
     SkDEBUGCODE(fVerbCnt = 0x9999999;)
     SkDEBUGCODE(fPointCnt = 0xAAAAAAA;)
     SkDEBUGCODE(fPointCnt = 0xBBBBBBB;)
     SkDEBUGCODE(fGenerationID = 0xEEEEEEEE;)
     SkDEBUGCODE(fEditorsAttached = 0x7777777;)
 }
 
-static SkPathRef* gEmpty = nullptr;
-
+SK_DECLARE_STATIC_ONCE_PTR(SkPathRef, empty);
 SkPathRef* SkPathRef::CreateEmpty() {
-    static SkOnce once;
-    once([]{
-        gEmpty = new SkPathRef;
-        gEmpty->computeBounds();   // Avoids races later to be the first to do this.
-    });
-    return SkRef(gEmpty);
+    return SkRef(empty.get([]{
+        SkPathRef* pr = new SkPathRef;
+        pr->computeBounds();   // Avoids races later to be the first to do this.
+        return pr;
+    }));
 }
 
 void SkPathRef::CreateTransformedCopy(SkAutoTUnref<SkPathRef>* dst,
                                       const SkPathRef& src,
                                       const SkMatrix& matrix) {
     SkDEBUGCODE(src.validate();)
     if (matrix.isIdentity()) {
         if (*dst != &src) {
             src.ref();
             dst->reset(const_cast<SkPathRef*>(&src));
@@ skipping 397 matching lines @@
             // empty ID
             do {
                 fGenerationID = (sk_atomic_inc(&gPathRefGenerationID) + 1) & kMask;
             } while (fGenerationID <= kEmptyGenID);
         }
     }
     return fGenerationID;
 }
 
 void SkPathRef::addGenIDChangeListener(GenIDChangeListener* listener) {
-    if (nullptr == listener || this == gEmpty) {
+    if (nullptr == listener || this == (SkPathRef*)empty) {
         delete listener;
         return;
     }
     *fGenIDChangeListeners.append() = listener;
 }
 
 // we need to be called *before* the genID gets changed or zerod
 void SkPathRef::callGenIDChangeListeners() {
     for (int i = 0; i < fGenIDChangeListeners.count(); i++) {
         fGenIDChangeListeners[i]->onChange();
@@ skipping 184 matching lines @@
                 break;
             default:
                 SkDEBUGFAIL("Unknown Verb");
                 break;
         }
     }
     SkASSERT(mask == fSegmentMask);
 #endif // SK_DEBUG_PATH
 }
 #endif