Fix race condition in parallel font initialization.

src/ports/SkFontConfigInterface_android.cpp

Index: src/ports/SkFontConfigInterface_android.cpp
diff --git a/src/ports/SkFontConfigInterface_android.cpp b/src/ports/SkFontConfigInterface_android.cpp
index 20e6c5eb84b6270b4b93b9979985e575d27f848c..d760d77c5fb1aab64855a37f3d939fd979c3a087 100644
--- a/src/ports/SkFontConfigInterface_android.cpp
+++ b/src/ports/SkFontConfigInterface_android.cpp
@@ -155,7 +155,8 @@ static SkFontConfigInterfaceAndroid* getSingletonInterface() {
     return gFontConfigInterface;
 }
 
-SkFontConfigInterface* SkFontConfigInterface::GetSingletonDirectInterface() {
+SkFontConfigInterface* SkFontConfigInterface::GetSingletonDirectInterface(SkBaseMutex& mutex) {
+    // Doesn't need passed-in mutex because getSingletonInterface() uses one

[mtklein, 2014/06/26 18:59:07]

Can we refactor to remove that other mutex and use this one instead?  I'd feel a
lot warmer and fuzzier if all variants worked the same way.

[tomhudson, 2014/06/26 21:01:52]

getSingletonInterface() has many (5?) other callers. They don't have access to
the mutex we're passing in here, so I don't see an obvious way to do that.

Now, locking the mutex passed in wouldn't *hurt* here, aside from the minor
performance hit.

     return getSingletonInterface();
 }