Fix handling of store-write failures in Pver4

components/safe_browsing_db/v4_store.cc

Index: components/safe_browsing_db/v4_store.cc
diff --git a/components/safe_browsing_db/v4_store.cc b/components/safe_browsing_db/v4_store.cc
index efb548a5bed168fb3f1af74cfe7d0809b08d7aa5..3b7ded7d6b1ee45c8b30fc1f496ade798d3b7e66 100644
--- a/components/safe_browsing_db/v4_store.cc
+++ b/components/safe_browsing_db/v4_store.cc
@@ -738,7 +738,10 @@ StoreWriteResult V4Store::WriteToDisk(const Checksum& checksum) {
   file_format.SerializeToString(&file_format_string);
   size_t written = base::WriteFile(new_filename, file_format_string.data(),
                                    file_format_string.size());
-  DCHECK_EQ(file_format_string.size(), written);
+
+  if (file_format_string.size() != written) {
+    return UNEXPECTED_BYTES_WRITTEN_FAILURE;
+  }
 
   if (!base::Move(new_filename, store_path_)) {
     return UNABLE_TO_RENAME_FAILURE;