Upstream various ios/web utilities and helpers

ios/web/navigation/nscoder_util.h

Index: ios/web/navigation/nscoder_util.h
diff --git a/ios/web/navigation/nscoder_util.h b/ios/web/navigation/nscoder_util.h
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index 0000000000000000000000000000000000000000..5a92f19f0b84c93080a61f59039b8361c283f99c
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+++ b/ios/web/navigation/nscoder_util.h
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+// Copyright (c) 2012 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_NAVIGATION_NSCODER_UTIL_H_
+#define IOS_WEB_NAVIGATION_NSCODER_UTIL_H_
+
+#import <Foundation/Foundation.h>
+
+#include <string>
+
+namespace web {
+namespace nscoder_util {
+
+// Archives a std::string in an Objective-C key archiver.
+void EncodeString(NSCoder* coder, NSString* key, const std::string& string);
+
+// Decode a std::string from an Objective-C key unarchiver.
+std::string DecodeString(NSCoder* decoder, NSString* key);
+
+}  // namespace nscoder_util
+}  // namespace web
+
+#endif  // IOS_WEB_NAVIGATION_NSCODER_UTIL_H_