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

BUG=
R=robertphillips@google.com

Review URL: https://codereview.chromium.org/22875037

git-svn-id: http://skia.googlecode.com/svn/trunk@10874 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkGrFontScaler.cpp b/src/gpu/SkGrFontScaler.cpp
index aeddd28..c48e633 100644
--- a/src/gpu/SkGrFontScaler.cpp
+++ b/src/gpu/SkGrFontScaler.cpp
@@ -88,7 +88,7 @@
         case SkMask::kLCD32_Format:
             return kA888_GrMaskFormat;
         default:
-            SkASSERT(!"unsupported SkMask::Format");
+            SkDEBUGFAIL("unsupported SkMask::Format");
             return kA8_GrMaskFormat;
     }
 }