Tidy: Mark IndexedDBExternalObject constructors explicit

Bug: N/A
Change-Id: I08d9bb1facccd82648389453ea88067e7e1786d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2601577
Auto-Submit: Austin Sullivan <asully@chromium.org>
Commit-Queue: Daniel Murphy <dmurph@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839675}

content/browser/indexed_db/indexed_db_external_object.h

@@ -64,10 +64,11 @@ class CONTENT_EXPORT IndexedDBExternalObject {
                           const base::Time& last_modified,
                           const int64_t size);
   // These are for Native File System handles.
-  IndexedDBExternalObject(
+  explicit IndexedDBExternalObject(
       mojo::PendingRemote<blink::mojom::NativeFileSystemTransferToken>
           token_remote);
-  IndexedDBExternalObject(std::vector<uint8_t> native_file_system_token);
+  explicit IndexedDBExternalObject(
+      std::vector<uint8_t> native_file_system_token);
 
   IndexedDBExternalObject(const IndexedDBExternalObject& other);
   ~IndexedDBExternalObject();