Fix texture allocation in SWMaskHelper

https://codereview.chromium.org/19789006/



git-svn-id: http://skia.googlecode.com/svn/trunk@10197 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index c4d8318..9564a50 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -211,6 +211,7 @@
         art.set(this->drawState(), renderTarget);
     }
     if (NULL == this->getDrawState().getRenderTarget()) {
+        GrAssert(0);
         return;
     }
     this->handleDirtyContext();