Upstream various ios/web utilities and helpers

ios/web/history_state_util.h

Index: ios/web/history_state_util.h
diff --git a/ios/web/history_state_util.h b/ios/web/history_state_util.h
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+// Copyright 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_HISTORY_STATE_UTIL_H_
+#define IOS_WEB_HISTORY_STATE_UTIL_H_
+
+#import <Foundation/Foundation.h>

[Eugene But (OOO till 7-30), 2015/03/09 16:17:43]

Optional: No need for this mport

+
+#include <string>
+
+class GURL;
+
+namespace web {
+namespace history_state_util {
+
+// Checks if toUrl is a valid argument to history.pushState() or
+// history.replaceState() given the current URL.
+bool IsHistoryStateChangeValid(const GURL& currentUrl,
+                               const GURL& toUrl);
+
+// Generates the appropriate full URL for a history.pushState() or
+// history.replaceState() transition from currentURL to destination, resolved
+// against baseURL. |destination| may be a relative URL. Will return an invalid
+// URL if the resolved destination, or the transition, is not valid.
+GURL GetHistoryStateChangeUrl(const GURL& currentUrl,
+                              const GURL& baseUrl,
+                              const std::string& destination);
+
+}  // namespace history_state_util
+}  // namespace web
+
+#endif  // IOS_WEB_HISTORY_STATE_UTIL_H_