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/doc/SkDocument.cpp b/src/doc/SkDocument.cpp
index e94c89b..055c749 100644
--- a/src/doc/SkDocument.cpp
+++ b/src/doc/SkDocument.cpp
@@ -49,7 +49,7 @@
                 return NULL;
         }
     }
-    SkASSERT(!"never get here");
+    SkDEBUGFAIL("never get here");
     return NULL;
 }