Add unit tests to text context

TBR=bsalomon@google.com
BUG=skia:

Review URL: https://codereview.chromium.org/1128153005
diff --git a/src/gpu/GrBatchTest.h b/src/gpu/GrBatchTest.h
index 3199354..9daa960 100644
--- a/src/gpu/GrBatchTest.h
+++ b/src/gpu/GrBatchTest.h
@@ -29,7 +29,9 @@
 #define BATCH_TEST_EXTERN(Batch) \
     extern GrBatch* Batch##__Test(SkRandom*, GrContext* context);
 #define BATCH_TEST_ENTRY(Batch) \
-        Batch##__Test
+    Batch##__Test
+#define BATCH_TEST_FRIEND(Batch) \
+    friend GrBatch* Batch##__Test(SkRandom* random, GrContext* context);
 
 GrBatch* GrRandomBatch(SkRandom*, GrContext*);