Updated error translation logic.

base/ios/nserror_util.h

Index: base/ios/nserror_util.h
diff --git a/base/ios/nserror_util.h b/base/ios/nserror_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..97675ff61bbc2dfa8ece85b1d58652eea164a0d0
--- /dev/null
+++ b/base/ios/nserror_util.h
@@ -0,0 +1,25 @@
+// Copyright 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.
+
+#ifndef BASE_IOS_NSERROR_UTIL_H_
+#define BASE_IOS_NSERROR_UTIL_H_
+
+@class NSError;
+
+namespace base {
+namespace nserror_util {

[Eugene But (OOO till 7-30), 2015/06/23 21:27:14]

I think the namespace for this should be ios. I know about inconsistency in
namespace usage (f.e. base::device_util)

[stuartmorgan, 2015/06/24 19:13:09]

Yes, either base::ios or base::ios::nserror_util

[kkhorimoto, 2015/06/24 20:01:42]

Done.

+
+// Iterates through |error|'s underlying errors and returns the first error for
+// which there is no underlying error.
+NSError* GetFinalUnderlyingErrorFromError(NSError* error);
+
+// Returns a copy of |original_error| with |underlying_error| appended to the
+// end of its underlying error chain.
+NSError* ErrorWithAppendedUnderlyingError(NSError* original_error,
+                                          NSError* underlying_error);
+
+}  // namespace nserror_util
+}  // namespace base
+
+#endif  // BASE_IOS_NSERROR_UTIL_H_