Add CryptAuth managers to EasyUnlockServiceRegular

components/proximity_auth/cryptauth/cryptauth_enrollment_utils.cc

Index: components/proximity_auth/cryptauth/cryptauth_enrollment_utils.cc
diff --git a/components/proximity_auth/cryptauth/cryptauth_enrollment_utils.cc b/components/proximity_auth/cryptauth/cryptauth_enrollment_utils.cc
index 476721c97c5caef0306f5bc113514e99fa7b52ac..4313ebb06d24de992221349f6cf4b62c0ac3e3d5 100644
--- a/components/proximity_auth/cryptauth/cryptauth_enrollment_utils.cc
+++ b/components/proximity_auth/cryptauth/cryptauth_enrollment_utils.cc
@@ -4,11 +4,32 @@
 
 #include "components/proximity_auth/cryptauth/cryptauth_enrollment_utils.h"
 
+#include <math.h>
+
+#include "base/md5.h"
 #include "base/sha1.h"
 #include "components/proximity_auth/cryptauth/base64url.h"
 
 namespace proximity_auth {
 
+int64_t HashStringToInt64(const std::string& string) {
+  base::MD5Context context;
+  base::MD5Init(&context);
+  base::MD5Update(&context, string);
+
+  base::MD5Digest digest;
+  base::MD5Final(&digest, &context);

[sacomoto, 2015/08/27 15:38:05]

Why don't you use |base::MD5Sum()|?

[Tim Song, 2015/08/27 18:12:27]

I feel it's a bit safer to use the MD5Context interface, since we don't have to
pass the raw c_str().

[sacomoto, 2015/08/28 14:47:17]

Ok. It makes sense.

+
+  // Fold the digest into an int64 value.

[sacomoto, 2015/08/27 15:38:05]

Please add a comment saying that |digest.a| has 128 bits, and you are splitting
it in two 64bits parts and summing them up.

[Tim Song, 2015/08/27 18:12:27]

Done.

+  int64_t hash = 0;
+  for (size_t i = 0; i < sizeof(digest.a); ++i) {
+    uint8_t byte = digest.a[i];
+    hash += static_cast<int64_t>(byte) << (i % sizeof(int64_t));
+  }
+
+  return hash;
+}
+
 std::string CalculateDeviceUserId(const std::string& device_id,
                                   const std::string& user_id) {
   std::string device_user_id;