Build fix for Surface Test on non-gpu builds

git-svn-id: http://skia.googlecode.com/svn/trunk@8513 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/SurfaceTest.cpp b/tests/SurfaceTest.cpp
index 59e565b..95c76cb 100644
--- a/tests/SurfaceTest.cpp
+++ b/tests/SurfaceTest.cpp
@@ -35,8 +35,12 @@
     case kRaster_SurfaceType:
         return SkSurface::NewRaster(imageSpec);
     case kGpu_SurfaceType:
+#if SK_SUPPORT_GPU
         SkASSERT(NULL != context);
         return SkSurface::NewRenderTarget(context, imageSpec);
+#else
+        SkASSERT(0);
+#endif
     case kPicture_SurfaceType:
         return SkSurface::NewPicture(10, 10);
     }