Added histogram on successful check. Safe verification

chrome/browser/protector/protector.cc

Index: chrome/browser/protector/protector.cc
diff --git a/chrome/browser/protector/protector.cc b/chrome/browser/protector/protector.cc
index e26fe18b8eea59a542401231c2675f1164139366..1b2d04185146a018f23401506752200f674e3f3b 100644
--- a/chrome/browser/protector/protector.cc
+++ b/chrome/browser/protector/protector.cc
@@ -69,12 +69,27 @@ void Protector::OnChangesAction(SettingChangeAction action) {
 
 std::string SignSetting(const std::string& value) {
   crypto::HMAC hmac(crypto::HMAC::SHA256);
-  DCHECK(hmac.Init(kProtectorSigningKey));
+  if (!hmac.Init(kProtectorSigningKey)) {
+    LOG(WARNING) << "Failed to initialize HMAC algorithm for signing";

[Ilya Sherman, 2011/11/01 18:19:11]

Are you sure you want LOG(WARNING) here rather than NOTREACHED()?  Are you
expecting this to fail in builds that we ship to users; and if so, are you
expecting the logged lines to be helpful in resolving the issue?

[whywhat, 2011/11/02 08:14:29]

HMAC implementation is platform dependent so may certainly fail on user's
machines. Logging would help to identify this cases when figuring out why
Protector bubble shows up without obvious reason.  

+    return std::string();
+  }
 
   std::vector<unsigned char> digest(hmac.DigestLength());
-  DCHECK(hmac.Sign(value, &digest[0], digest.size()));
+  if (!hmac.Sign(value, &digest[0], digest.size())) {
+    LOG(WARNING) << "Failed to sign setting";
+    return std::string();
+  }
 
   return std::string(&digest[0], &digest[0] + digest.size());
 }
 
+bool IsSettingValid(const std::string& value, const std::string& signature) {
+  crypto::HMAC hmac(crypto::HMAC::SHA256);
+  if (!hmac.Init(kProtectorSigningKey)) {
+    LOG(WARNING) << "Failed to initialize HMAC algorithm for verification.";
+    return false;
+  }
+  return hmac.Verify(value, signature);
+}
+
 }  // namespace protector