handle null vertex or index buffers in batch

src/gpu/GrInOrderDrawBuffer.cpp

Index: src/gpu/GrInOrderDrawBuffer.cpp
diff --git a/src/gpu/GrInOrderDrawBuffer.cpp b/src/gpu/GrInOrderDrawBuffer.cpp
index 24db2e08dd83730a193372563ed95c80ef12693b..45a5de77dbe9b6ff8177e391f8c57b1c32efd7d2 100644
--- a/src/gpu/GrInOrderDrawBuffer.cpp
+++ b/src/gpu/GrInOrderDrawBuffer.cpp
@@ -147,6 +147,11 @@ public:
                                                               &vertexBuffer,
                                                               &firstVertex);
 
+        if (!vertices || !batchTarget->quadIndexBuffer()) {
+            SkDebugf("Could not allocate buffers\n");
+            return;
+        }
+
         for (int i = 0; i < instanceCount; i++) {
             const Geometry& args = fGeoData[i];