Port most uses of SkOnce to SkLazyPtr.

src/core/SkLazyPtr.h

Index: src/core/SkLazyPtr.h
diff --git a/src/core/SkLazyPtr.h b/src/core/SkLazyPtr.h
index 71876e7b41f248c95e09c9b719fe588b34a8ce91..50d8328cd5909e1729d4103ec325d3824bc10be1 100644
--- a/src/core/SkLazyPtr.h
+++ b/src/core/SkLazyPtr.h
@@ -64,7 +64,6 @@
 
 // See FIXME below.
 class SkFontConfigInterface;
-class SkTypeface;
 
 namespace Private {
 
@@ -100,7 +99,6 @@ public:
 #ifdef SK_DEVELOPER
     // FIXME: We know we leak refs on some classes.  For now, let them leak.
     void cleanup(SkFontConfigInterface*) {}
-    void cleanup(SkTypeface*) {}
     template <typename U> void cleanup(U* ptr) { Destroy(ptr); }
 
     ~SkLazyPtr() {