Fix race condition in parallel font initialization.

src/ports/SkFontHost_fontconfig.cpp

Index: src/ports/SkFontHost_fontconfig.cpp
diff --git a/src/ports/SkFontHost_fontconfig.cpp b/src/ports/SkFontHost_fontconfig.cpp
index 07bfbd044cb32ec3c0f4bb4f76a62acc4b6116cd..8abf5cf7f0923c1d82592ff2d2ccb47bfc7b046f 100644
--- a/src/ports/SkFontHost_fontconfig.cpp
+++ b/src/ports/SkFontHost_fontconfig.cpp
@@ -50,7 +50,7 @@ static SkFontConfigInterface* RefFCI() {
         if (fci) {
             return fci;
         }
-        fci = SkFontConfigInterface::GetSingletonDirectInterface();
+        fci = SkFontConfigInterface::GetSingletonDirectInterface(&gFontConfigInterfaceMutex);
         SkFontConfigInterface::SetGlobal(fci);
     }
 }