Modernize and trim down SkOnce.

src/utils/win/SkDWrite.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkTypes.h"
 #if defined(SK_BUILD_FOR_WIN32)
 
 #include "SkDWrite.h"
@@ skipping 25 matching lines @@
     }
 
     HRVM(dWriteCreateFactoryProc(DWRITE_FACTORY_TYPE_SHARED,
                                  __uuidof(IDWriteFactory),
                                  reinterpret_cast<IUnknown**>(factory)),
          "Could not create DirectWrite factory.");
     atexit(release_dwrite_factory);
 }
 
 
-SK_DECLARE_STATIC_ONCE(once);
 IDWriteFactory* sk_get_dwrite_factory() {
-    SkOnce(&once, create_dwrite_factory, &gDWriteFactory);
+    static SkOnce once;
+    once(create_dwrite_factory, &gDWriteFactory);
     return gDWriteFactory;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // String conversion
 
 /** Converts a utf8 string to a WCHAR string. */
 HRESULT sk_cstring_to_wchar(const char* skname, SkSMallocWCHAR* name) {
     int wlen = MultiByteToWideChar(CP_UTF8, 0, skname, -1, nullptr, 0);
     if (0 == wlen) {
@@ skipping 60 matching lines @@
         HRESULT hr = HRESULT_FROM_WIN32(GetLastError());
         if (!IS_ERROR(hr)) {
             hr = ERROR_PROC_NOT_FOUND;
         }
         return hr;
     }
     return S_OK;
 }
 
 #endif//defined(SK_BUILD_FOR_WIN32)