sql: Add documentation link for header values

Change-Id: I3dc5bb7ea989c371d818698119756970a93da706
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3488145
Auto-Submit: Austin Sullivan <asully@chromium.org>
Commit-Queue: Austin Sullivan <asully@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/main@{#974757}
diff --git a/sql/sandboxed_vfs_file.cc b/sql/sandboxed_vfs_file.cc
index 45a9551..b651eb6 100644
--- a/sql/sandboxed_vfs_file.cc
+++ b/sql/sandboxed_vfs_file.cc
@@ -165,6 +165,7 @@
   DCHECK_GE(offset, 0);
 
 #if DCHECK_IS_ON()
+  // See http://www.sqlite.org/fileformat2.html#database_header
   constexpr int kSqliteDatabaseHeaderOffset = 0;
   constexpr int kSqliteDatabaseHeaderSize = 100;
   // SQLite's locking protocol only acquires locks on the database file. The