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/tests/AAClipTest.cpp b/tests/AAClipTest.cpp
index 4c4ee60..b507570 100644
--- a/tests/AAClipTest.cpp
+++ b/tests/AAClipTest.cpp
@@ -39,7 +39,7 @@
             wbytes <<= 2;
             break;
         default:
-            SkASSERT(!"unknown mask format");
+            SkDEBUGFAIL("unknown mask format");
             return false;
     }