Fix intermittent GrAutoLocaleSetter crashes on Windows

src/gpu/GrAutoLocaleSetter.h

Index: src/gpu/GrAutoLocaleSetter.h
diff --git a/src/gpu/GrAutoLocaleSetter.h b/src/gpu/GrAutoLocaleSetter.h
index 51164e9813a056016a4a71a26855cc315a4ad6e4..ca232d218add82cd16f6c80c15cb8d31bb92c261 100644
--- a/src/gpu/GrAutoLocaleSetter.h
+++ b/src/gpu/GrAutoLocaleSetter.h
@@ -10,6 +10,10 @@
 
 #include "GrTypes.h"
 
+#if defined(SK_BUILD_FOR_WIN)
+#include "SkString.h"
+#endif
+
 #if !defined(SK_BUILD_FOR_ANDROID)
 #include <locale.h>
 #endif
@@ -42,8 +46,8 @@ public:
 
     ~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__)
@@ -57,7 +61,7 @@ public:
 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;