diff --git a/payload_consumer/delta_performer.cc b/payload_consumer/delta_performer.cc
index 5303e03..2445c6d 100644
--- a/payload_consumer/delta_performer.cc
+++ b/payload_consumer/delta_performer.cc
@@ -1031,15 +1031,10 @@
   return true;
 }
 
-namespace {
-
-// Compare |calculated_hash| with source hash in |operation|, return false and
-// dump hash and set |error| if don't match.
-// |source_fd| is the file descriptor of the source partition.
-bool ValidateSourceHash(const brillo::Blob& calculated_hash,
-                        const InstallOperation& operation,
-                        const FileDescriptorPtr source_fd,
-                        ErrorCode* error) {
+bool DeltaPerformer::ValidateSourceHash(const brillo::Blob& calculated_hash,
+                                        const InstallOperation& operation,
+                                        const FileDescriptorPtr source_fd,
+                                        ErrorCode* error) {
   brillo::Blob expected_source_hash(operation.src_sha256_hash().begin(),
                                     operation.src_sha256_hash().end());
   if (calculated_hash != expected_source_hash) {
@@ -1074,8 +1069,6 @@
   return true;
 }
 
-}  // namespace
-
 bool DeltaPerformer::PerformSourceCopyOperation(
     const InstallOperation& operation, ErrorCode* error) {
   if (operation.has_src_length())
diff --git a/payload_consumer/delta_performer.h b/payload_consumer/delta_performer.h
index 55a19d8..b156e2f 100644
--- a/payload_consumer/delta_performer.h
+++ b/payload_consumer/delta_performer.h
@@ -165,6 +165,14 @@
   // it returns that value, otherwise it returns the default value.
   uint32_t GetMinorVersion() const;
 
+  // Compare |calculated_hash| with source hash in |operation|, return false and
+  // dump hash and set |error| if don't match.
+  // |source_fd| is the file descriptor of the source partition.
+  static bool ValidateSourceHash(const brillo::Blob& calculated_hash,
+                                 const InstallOperation& operation,
+                                 const FileDescriptorPtr source_fd,
+                                 ErrorCode* error);
+
  private:
   friend class DeltaPerformerTest;
   friend class DeltaPerformerIntegrationTest;