diff --git a/payload_generator/delta_diff_generator_unittest.cc b/payload_generator/delta_diff_generator_unittest.cc
index 94dd1e4..050f25b 100644
--- a/payload_generator/delta_diff_generator_unittest.cc
+++ b/payload_generator/delta_diff_generator_unittest.cc
@@ -28,6 +28,7 @@
 #include "update_engine/extent_ranges.h"
 #include "update_engine/payload_constants.h"
 #include "update_engine/payload_generator/extent_mapper.h"
+#include "update_engine/payload_generator/extent_utils.h"
 #include "update_engine/payload_generator/graph_types.h"
 #include "update_engine/subprocess.h"
 #include "update_engine/test_utils.h"
@@ -48,15 +49,6 @@
 
 namespace {
 
-int64_t BlocksInExtents(
-    const google::protobuf::RepeatedPtrField<Extent>& extents) {
-  int64_t ret = 0;
-  for (int i = 0; i < extents.size(); i++) {
-    ret += extents.Get(i).num_blocks();
-  }
-  return ret;
-}
-
 uint64_t AddExtent(uint64_t start_block, uint64_t num_blocks,
                    vector<Extent>* extents) {
   extents->push_back(ExtentForRange(start_block, num_blocks));