base::MD5Clone() clones MD5Context.

base/md5.cc

Index: base/md5.cc
diff --git a/base/md5.cc b/base/md5.cc
index 754994c0e562b45b2bc4b90cc2a7c612d14ec5a7..aec6d43f94d6f92fead99cfb2bb397d33ecf7282 100644
--- a/base/md5.cc
+++ b/base/md5.cc
@@ -215,6 +215,10 @@ void MD5Update(MD5Context* context, const StringPiece& data) {
         memcpy(ctx->in, buf, len);
 }
 
+void MD5Clone(MD5Context* clone_context, MD5Context* original_context) {
+  memcpy(clone_context, original_context, sizeof(MD5Context));
+}
+
 /*
  * Final wrapup - pad to 64-byte boundary with the bit pattern
  * 1 0* (64-bit count of bits processed, MSB-first)