Fix intermittent GrAutoLocaleSetter crashes on Windows

src/gpu/GrAutoLocaleSetter.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrAutoLocaleSetter_DEFINED
 #define GrAutoLocaleSetter_DEFINED
 
 #include "GrTypes.h"
 
+#if defined(SK_BUILD_FOR_WIN)
+#include "SkString.h"
+#endif
+
 #if !defined(SK_BUILD_FOR_ANDROID)
 #include <locale.h>
 #endif
 
 #if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
 #include <xlocale.h>
 #endif
 
 /**
  * Helper class for ensuring that we don't use the wrong locale when building shaders. Android
@@ skipping 12 matching lines @@
         } else {
             fOldLocale = static_cast<locale_t>(0);
         }
 #else
         (void) name; // suppress unused param warning.
 #endif
     }
 
     ~GrAutoLocaleSetter () {
 #if defined(SK_BUILD_FOR_WIN)
-        if (fOldLocale) {
-            setlocale(LC_ALL, fOldLocale);
+        if (!fOldLocale.isEmpty()) {

[bsalomon, 2015/12/10 15:12:23]

IIUC empty string is valid.
"If locale points to an empty string, the locale is the implementation-defined
native environment."

Maybe that never gets returned by  setlocale, though?

[Kimmo Kinnunen, 2015/12/11 07:50:17]

Done.

+            setlocale(LC_ALL, fOldLocale.c_str());
         }
         _configthreadlocale(fOldPerThreadLocale);
 #elif !defined(SK_BUILD_FOR_ANDROID) && !defined(__UCLIBC__)
         if (fLocale) {
              uselocale(fOldLocale);
              freelocale(fLocale);
         }
 #endif
     }
 
 private:
 #if defined(SK_BUILD_FOR_WIN)
     int fOldPerThreadLocale;
-    const char* fOldLocale;
+    SkString fOldLocale;
 #elif !defined(SK_BUILD_FOR_ANDROID) && !defined(__UCLIBC__)
     locale_t fOldLocale;
     locale_t fLocale;
 #endif
 };
 
 #endif