Updated error translation logic.

ios/web/public/web_state/error_translation_util.h

Index: ios/web/public/web_state/error_translation_util.h
diff --git a/ios/web/public/web_state/error_translation_util.h b/ios/web/public/web_state/error_translation_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..e4a8222e64c946a0b354d18f22af2283254c6580
--- /dev/null
+++ b/ios/web/public/web_state/error_translation_util.h
@@ -0,0 +1,24 @@
+// 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 IOS_WEB_PUBLIC_WEB_STATE_ERROR_TRANSLATION_UTIL_H_
+#define IOS_WEB_PUBLIC_WEB_STATE_ERROR_TRANSLATION_UTIL_H_
+
+#import <Foundation/Foundation.h>
+
+namespace web {
+
+// Iterates through |error|'s underlying errors and returns the first error for
+// which there is no underlying error.
+NSError* GetUltimateUnderlyingErrorForError(NSError* error);

[Eugene But (OOO till 7-30), 2015/06/19 00:52:01]

NIT: How about Final instead of Ultimate?

[Eugene But (OOO till 7-30), 2015/06/19 00:52:01]

NIT: s/For/From

[kkhorimoto, 2015/06/23 20:33:58]

Done.

+
+// Translates iOS-specific errors into their net error equivalent.  If a valid
+// translation is found, a copy of |error| is returned with the translation as
+// its ultimate underlying error.  If there is no viable translation, the
+// original error is returned.
+NSError* NetErrorFromError(NSError* error);

[Eugene But (OOO till 7-30), 2015/06/19 00:52:01]

I believe this method should not be a part of web's public interface. Embedder
should not care about iOS specific error codes. WDYT?

[kkhorimoto, 2015/06/23 20:33:58]

The main reason I moved these files to the public directory is so that we can
use GetFinalUnderlyingErrorFromError from outside of web/.  I agree, though,
that this isn't something that we necessarily need to be public.  I'll move this
back into the non-public directory and introduce a more general NSError utility
file for GetFinalUnderlyingErrorFromError.

+
+}  // namespace web
+
+#endif  // IOS_WEB_PUBLIC_WEB_STATE_ERROR_TRANSLATION_UTIL_H_