Add SkDEBUGFAIL to clean up use of SkASSERT(!"text");
catch a couple of latent SkASSERT("text") bugs.

http://codereview.appspot.com/5504090/



git-svn-id: http://skia.googlecode.com/svn/trunk@2926 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkGradientShader.cpp b/src/effects/SkGradientShader.cpp
index 2d99d3d..1e1add2 100644
--- a/src/effects/SkGradientShader.cpp
+++ b/src/effects/SkGradientShader.cpp
@@ -2068,7 +2068,7 @@
     else if (192 == add)
         SkASSERT(x > 0 && y < 0);
     else
-        SkASSERT(!"bad value for add");
+        SkDEBUGFAIL("bad value for add");
 #endif
 
     /*  This ^ trick makes x, y positive, and the swap<> handles quadrants