Remove vertex/index buffer factilities from GrDrawTarget.

Review URL: https://codereview.chromium.org/1105263002
diff --git a/src/gpu/GrTestBatch.h b/src/gpu/GrTestBatch.h
index 716912d..8e16f52 100644
--- a/src/gpu/GrTestBatch.h
+++ b/src/gpu/GrTestBatch.h
@@ -9,6 +9,7 @@
 #define GrTestBatch_DEFINED
 
 #include "GrBatch.h"
+#include "GrVertexBuffer.h"
 
 /*
  * A simple batch only for testing purposes which actually doesn't batch at all, but can fit into