Created SerializedUserDataManager.

ios/web/navigation/crw_serialized_navigation_manager.mm

Index: ios/web/navigation/crw_serialized_navigation_manager.mm
diff --git a/ios/web/navigation/crw_serialized_navigation_manager.mm b/ios/web/navigation/crw_serialized_navigation_manager.mm
index 9c8320369ea1eb501a97cbd4e2455e50418a8f4f..3ec416c84b1ea6f071aaa82d5a4645db039ddbd3 100644
--- a/ios/web/navigation/crw_serialized_navigation_manager.mm
+++ b/ios/web/navigation/crw_serialized_navigation_manager.mm
@@ -20,6 +20,7 @@ NSString* const kPreviousNavigationIndexKey = @"previousNavigationIndex";
 NSString* const kTabIdKey = @"tabId";
 NSString* const kWindowNameKey = @"windowName";
 NSString* const kXCallbackParametersKey = @"xCallbackParameters";
+NSString* const kSerializedUserDataKey = @"serializedUserData";
 }
 
 @interface CRWSerializedNavigationManager () {
@@ -41,6 +42,7 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 @synthesize entries = _entries;
 @synthesize sessionCertificatePolicyManager = _sessionCertificatePolicyManager;
 @synthesize xCallbackParameters = _xCallbackParameters;
+@synthesize serializedUserData = _serializedUserData;
 
 - (instancetype)init {
   self = [super init];
@@ -79,6 +81,8 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
     }
     self.xCallbackParameters =
         [[aDecoder decodeObjectForKey:kXCallbackParametersKey] retain];
+    self.serializedUserData =
+        [aDecoder decodeObjectForKey:kSerializedUserDataKey];
   }
   return self;
 }
@@ -101,6 +105,7 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
                 forKey:kCertificatePolicyManagerKey];
   [aCoder encodeObject:self.xCallbackParameters forKey:kXCallbackParametersKey];
   // rendererInitiated is deliberately not preserved, as upstream.
+  [aCoder encodeObject:self.serializedUserData forKey:kSerializedUserDataKey];
 }
 
 @end