Revert of Port uses of SkLazyPtr to SkOncePtr.

src/core/SkFontMgr.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFontDescriptor.h"
 #include "SkFontMgr.h"
-#include "SkOncePtr.h"
+#include "SkLazyPtr.h"
 #include "SkStream.h"
 #include "SkTypes.h"
 
 class SkFontStyle;
 class SkTypeface;
 
 class SkEmptyFontStyleSet : public SkFontStyleSet {
 public:
     int count() override { return 0; }
     void getStyle(int, SkFontStyle*, SkString*) override {
@@ skipping 130 matching lines @@
         return nullptr;
     }
     return this->onCreateFromFile(path, ttcIndex);
 }
 
 SkTypeface* SkFontMgr::legacyCreateTypeface(const char familyName[],
                                             unsigned styleBits) const {
     return this->onLegacyCreateTypeface(familyName, styleBits);
 }
 
-SK_DECLARE_STATIC_ONCE_PTR(SkFontMgr, singleton);
+// As a template argument this must have external linkage.
+SkFontMgr* sk_fontmgr_create_default() {
+    SkFontMgr* fm = SkFontMgr::Factory();
+    return fm ? fm : new SkEmptyFontMgr;
+}
+
+SK_DECLARE_STATIC_LAZY_PTR(SkFontMgr, singleton, sk_fontmgr_create_default);
+
 SkFontMgr* SkFontMgr::RefDefault() {
-    return SkRef(singleton.get([]{
-        SkFontMgr* fm = SkFontMgr::Factory();
-        return fm ? fm : new SkEmptyFontMgr;
-    }));
+    return SkRef(singleton.get());
 }