My clang now doesn't complain about !"foo".

src/utils/ios/SkOSFile_iOS.mm

Index: src/utils/ios/SkOSFile_iOS.mm
diff --git a/src/utils/ios/SkOSFile_iOS.mm b/src/utils/ios/SkOSFile_iOS.mm
index a68576130903aa6e1f4bf3491e454668b6de3070..e38ecfdab4deaab4e6bbd5486f7f1a012fc6a3f9 100755
--- a/src/utils/ios/SkOSFile_iOS.mm
+++ b/src/utils/ios/SkOSFile_iOS.mm
@@ -82,12 +82,12 @@ size_t sk_fread(void* buffer, size_t byteCount, SkFILE* rec) {
 }
 
 size_t sk_fwrite(const void* buffer, size_t byteCount, SkFILE* f) {
-    SkASSERT(!"Not supported yet");
+    SkDEBUGFAIL("Not supported yet");
     return 0;
 }
 
 void sk_fflush(SkFILE* f) {
-    SkASSERT(!"Not supported yet");
+    SkDEBUGFAIL("Not supported yet");
 }
 
 void sk_fclose(SkFILE* rec) {