diff --git a/common/error_code.h b/common/error_code.h
index 252cc42..3dd7402 100644
--- a/common/error_code.h
+++ b/common/error_code.h
@@ -80,6 +80,9 @@
   kRollbackNotPossible = 54,
   kFirstActiveOmahaPingSentPersistenceError = 55,
   kVerityCalculationError = 56,
+  kInternalLibCurlError = 57,
+  kUnresolvedHostError = 58,
+  kUnresolvedHostRecovered = 59,
 
   // VERY IMPORTANT! When adding new error codes:
   //
diff --git a/common/error_code_utils.cc b/common/error_code_utils.cc
index b0bbbd4..5bcbaa4 100644
--- a/common/error_code_utils.cc
+++ b/common/error_code_utils.cc
@@ -161,6 +161,12 @@
       return "ErrorCode::kFirstActiveOmahaPingSentPersistenceError";
     case ErrorCode::kVerityCalculationError:
       return "ErrorCode::kVerityCalculationError";
+    case ErrorCode::kInternalLibCurlError:
+      return "ErrorCode::kInternalLibCurlError";
+    case ErrorCode::kUnresolvedHostError:
+      return "ErrorCode::kUnresolvedHostError";
+    case ErrorCode::kUnresolvedHostRecovered:
+      return "ErrorCode::kUnresolvedHostRecovered";
       // Don't add a default case to let the compiler warn about newly added
       // error codes which should be added here.
   }
diff --git a/common/http_fetcher.h b/common/http_fetcher.h
index 94f31d7..f74a0f0 100644
--- a/common/http_fetcher.h
+++ b/common/http_fetcher.h
@@ -59,6 +59,12 @@
   HttpFetcherDelegate* delegate() const { return delegate_; }
   int http_response_code() const { return http_response_code_; }
 
+  // Returns additional error code that can't be expressed in terms of an HTTP
+  // response code. For example, if there was a specific internal error code in
+  // the objects used in the implementation of this class (like libcurl) that we
+  // are interested about, we can communicate it through this value.
+  ErrorCode GetAuxiliaryErrorCode() const { return auxiliary_error_code_; }
+
   // Optional: Post data to the server. The HttpFetcher should make a copy
   // of this data and upload it via HTTP POST during the transfer. The type of
   // the data is necessary for properly setting the Content-Type HTTP header.
@@ -159,6 +165,10 @@
   // set to the response code when the transfer is complete.
   int http_response_code_;
 
+  // Set when there is an error that can't be expressed in the form of
+  // |http_response_code_|.
+  ErrorCode auxiliary_error_code_{ErrorCode::kSuccess};
+
   // The delegate; may be null.
   HttpFetcherDelegate* delegate_;
 
@@ -209,13 +219,6 @@
   // situations. It's OK to destroy the |fetcher| object in this callback.
   virtual void TransferComplete(HttpFetcher* fetcher, bool successful) = 0;
   virtual void TransferTerminated(HttpFetcher* fetcher) {}
-
-  // This allows |HttpFetcher| to send UMA metrics for its internal states
-  // (unrecoverable libcurl internal error, etc.).
-  virtual void ReportUpdateCheckMetrics(
-      metrics::CheckResult result,
-      metrics::CheckReaction reaction,
-      metrics::DownloadErrorCode download_error_code) {}
 };
 
 }  // namespace chromeos_update_engine