Moved serialization out of CRWSessionEntry.

ios/web/public/crw_navigation_item_storage.h

Index: ios/web/public/crw_navigation_item_storage.h
diff --git a/ios/web/public/crw_navigation_item_storage.h b/ios/web/public/crw_navigation_item_storage.h
new file mode 100644
index 0000000000000000000000000000000000000000..9cc7927f891ef689d21cefdeef932ca7e8921a37
--- /dev/null
+++ b/ios/web/public/crw_navigation_item_storage.h
@@ -0,0 +1,66 @@
+// Copyright 2017 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_CRW_NAVIGATION_ITEM_STORAGE_H_
+#define IOS_WEB_PUBLIC_CRW_NAVIGATION_ITEM_STORAGE_H_
+
+#import <Foundation/Foundation.h>
+#include <stddef.h>
+
+#include "base/strings/string16.h"
+#include "base/time/time.h"
+#include "ios/web/public/referrer.h"
+#import "ios/web/public/web_state/page_display_state.h"
+#include "url/gurl.h"
+
+namespace web {
+
+// Keys used to serialize navigation properties.
+
+// Current URL (std::string).
+extern NSString* const kNavigationItemStorageURLKey;
+// Current URL. Deprecated, used for backward compatibility (NSURL).
+extern NSString* const kNavigationItemStorageURLDeperecatedKey;
+// Page referrer URL (std::string).
+extern NSString* const kNavigationItemStorageReferrerURLKey;
+// Page referrer URL (NSURL). Deprecated, used for backward compatibility.
+extern NSString* const kNavigationItemStorageReferrerURLDeprecatedKey;
+// Page referrer policy (int).
+extern NSString* const kNavigationItemStorageReferrerPolicyKey;
+// The time at which the last known local navigation has completed (int64_t).
+extern NSString* const kNavigationItemStorageTimestampKey;
+// Page title (NSString).
+extern NSString* const kNavigationItemStorageTitleKey;
+// The PageDisplayState (NSDictionary).
+extern NSString* const kNavigationItemStoragePageDisplayStateKey;
+// POST request data (NSData).
+extern NSString* const kNavigationItemStoragePOSTDataKey;
+// HTTP request headers (NSDictionary).
+extern NSString* const kNavigationItemStorageHTTPRequestHeadersKey;
+// Whether or not to bypass showing the resubmit data confirmation when loading
+// a POST request (BOOL).
+extern NSString* const kNavigationItemStorageSkipRepostFormConfirmationKey;
+// Should desktop user agent be used (BOOL)?
+extern NSString* const kNavigationItemStorageUseDesktopUserAgentKey;
+
+}  // namespace web
+
+// NSCoding-compliant class used to serialize NavigationItem's persisted
+// properties.
+@interface CRWNavigationItemStorage : NSObject<NSCoding>
+
+@property(nonatomic, assign) GURL virtualURL;
+@property(nonatomic, assign) web::Referrer referrer;
+@property(nonatomic, assign) base::Time timestamp;
+@property(nonatomic, assign) base::string16 title;
+@property(nonatomic, assign) web::PageDisplayState displayState;
+@property(nonatomic, assign) BOOL shouldSkipRepostFormConfirmation;
+@property(nonatomic, assign, getter=isOverridingUserAgent)
+    BOOL overridingUserAgent;
+@property(nonatomic, copy) NSData* POSTData;
+@property(nonatomic, copy) NSDictionary* HTTPRequestHeaders;
+
+@end
+
+#endif  // IOS_WEB_PUBLIC_CRW_NAVIGATION_ITEM_STORAGE_H_