Revert of Move prefix_set and parts of s_b_util into a new component safe_browsing_db.

components/safe_browsing_db/safe_browsing_db_util.cc

Index: components/safe_browsing_db/safe_browsing_db_util.cc
diff --git a/components/safe_browsing_db/safe_browsing_db_util.cc b/components/safe_browsing_db/safe_browsing_db_util.cc
deleted file mode 100644
index 623bfb3c8386d19a8f9c04d0242d27fbc2d12e3c..0000000000000000000000000000000000000000
--- a/components/safe_browsing_db/safe_browsing_db_util.cc
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/safe_browsing_db/safe_browsing_db_util.h"
-
-#include "crypto/sha2.h"
-
-SBFullHash SBFullHashForString(const base::StringPiece& str) {
-  SBFullHash h;
-  crypto::SHA256HashString(str, &h.full_hash, sizeof(h.full_hash));
-  return h;
-}