Reland of SkOncePtr -> SkOnce

src/core/SkXfermode.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkXfermode.h"
 #include "SkXfermode_proccoeff.h"
 #include "SkColorPriv.h"
 #include "SkMathPriv.h"
-#include "SkOncePtr.h"
+#include "SkOnce.h"
 #include "SkOpts.h"
 #include "SkReadBuffer.h"
 #include "SkString.h"
 #include "SkWriteBuffer.h"
 #include "SkPM4f.h"
 
 #define SkAlphaMulAlpha(a, b)   SkMulDiv255Round(a, b)
 
 static inline unsigned saturated_add(unsigned a, unsigned b) {
     SkASSERT(a <= 255);
@@ skipping 1273 matching lines @@
     str->append(" dst: ");
     if (CANNOT_USE_COEFF == fDstCoeff) {
         str->append("can't use");
     } else {
         str->append(gCoeffStrings[fDstCoeff]);
     }
 }
 #endif
 
 
-SK_DECLARE_STATIC_ONCE_PTR(SkXfermode, cached[SkXfermode::kLastMode + 1]);
-
 sk_sp<SkXfermode> SkXfermode::Make(Mode mode) {
-    SkASSERT(SK_ARRAY_COUNT(gProcCoeffs) == kModeCount);
-
     if ((unsigned)mode >= kModeCount) {
         // report error
         return nullptr;
     }
 
     // Skia's "default" mode is srcover. nullptr in SkPaint is interpreted as srcover
     // so we can just return nullptr from the factory.
     if (kSrcOver_Mode == mode) {
         return nullptr;
     }
 
-    return sk_ref_sp(cached[mode].get([=]{
+    SkASSERT(SK_ARRAY_COUNT(gProcCoeffs) == kModeCount);
+
+    static SkOnce        once[SkXfermode::kLastMode+1];
+    static SkXfermode* cached[SkXfermode::kLastMode+1];
+
+    once[mode]([mode] {
         ProcCoeff rec = gProcCoeffs[mode];
         if (auto xfermode = SkOpts::create_xfermode(rec, mode)) {
-            return xfermode;
+            cached[mode] = xfermode;
+        } else {
+            cached[mode] = new SkProcCoeffXfermode(rec, mode);
         }
-        return (SkXfermode*) new SkProcCoeffXfermode(rec, mode);
-    }));
+    });
+    return sk_ref_sp(cached[mode]);
 }
 
 SkXfermodeProc SkXfermode::GetProc(Mode mode) {
     SkXfermodeProc  proc = nullptr;
     if ((unsigned)mode < kModeCount) {
         proc = gProcCoeffs[mode].fProc;
     }
     return proc;
 }
 
@@ skipping 71 matching lines @@
     if (!xfer) {
         return SkXfermode::kOpaque_SrcColorOpacity == opacityType;
     }
 
     return xfer->isOpaque(opacityType);
 }
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkProcCoeffXfermode)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END