Use C locale for numerics when emitting shaders.

include/gpu/GrTypesPriv.h

Index: include/gpu/GrTypesPriv.h
diff --git a/include/gpu/GrTypesPriv.h b/include/gpu/GrTypesPriv.h
index 412de897c6543b851dad3134020c0f9d1788deca..151de1991ac3b7b79525786687f513055bb7b149 100644
--- a/include/gpu/GrTypesPriv.h
+++ b/include/gpu/GrTypesPriv.h
@@ -264,4 +264,51 @@ private:
     SkIRect fRect;
 };
 
+
+/**
+ * Helper class for ensuring that we don't use the wrong locale when building shaders. Android
+ * doesn't support locale in the NDK, so this is a no-op there.
+ */
+#if !defined(SK_BUILD_FOR_ANDROID)
+#include <locale.h>
+#endif
+
+#if defined(SK_BUILD_FOR_MAC)
+#include <xlocale.h>
+#endif
+
+class GrAutoLocaleSetter {
+public:
+    GrAutoLocaleSetter (const char* name) {
+#if defined(SK_BUILD_FOR_WIN)
+        fOldPerThreadLocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
+        fOldLocale = setlocale(LC_ALL, name);
+#elif !defined(SK_BUILD_FOR_ANDROID)
+        fLocale = newlocale(LC_ALL, name, 0);
+        fOldLocale = uselocale(fLocale);
+#else
+        (void) name; // suppress unused param warning.
+#endif
+    }
+
+    ~GrAutoLocaleSetter () {
+#if defined(SK_BUILD_FOR_WIN)
+        setlocale(LC_ALL, fOldLocale);
+        _configthreadlocale(fOldPerThreadLocale);
+#elif !defined(SK_BUILD_FOR_ANDROID)
+        SkASSERT(uselocale(fOldLocale) == fLocale);
+        freelocale(fLocale);
+#endif
+    }
+
+private:
+#if defined(SK_BUILD_FOR_WIN)
+    int fOldPerThreadLocale;
+    const char* fOldLocale;
+#elif !defined(SK_BUILD_FOR_ANDROID)
+    locale_t fOldLocale;
+    locale_t fLocale;
+#endif
+};
+
 #endif