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

src/core/SkBitmapFilter.cpp

Index: src/core/SkBitmapFilter.cpp
diff --git a/src/core/SkBitmapFilter.cpp b/src/core/SkBitmapFilter.cpp
index c2f68d4879a5ee965449dccf3cc7e8b8b50e919b..5128d9b5dc7a3843508db023dd0811b90ce1eea9 100644
--- a/src/core/SkBitmapFilter.cpp
+++ b/src/core/SkBitmapFilter.cpp
@@ -92,7 +92,7 @@ SkBitmapFilter *SkBitmapFilter::Allocate() {
     } else if (!strcmp(c_bitmapFilter, "box")) {
         return SkNEW(SkBoxFilter);
     } else {
-        SkASSERT(!!!"Unknown filter type");
+        SkDEBUGFAIL("Unknown filter type");
     }
 
     return NULL;