Moved serialization out of CRWSessionEntry.

ios/web/BUILD.gn

Index: ios/web/BUILD.gn
diff --git a/ios/web/BUILD.gn b/ios/web/BUILD.gn
index f9fd09f92e7c5ae06c2e3ba789fe5e51c2663775..7d0490790c9d061dc3a223bb23b4f1fd60342903 100644
--- a/ios/web/BUILD.gn
+++ b/ios/web/BUILD.gn
@@ -60,6 +60,8 @@ source_set("web_arc") {
     "navigation/navigation_item_facade_delegate.h",
     "navigation/navigation_item_impl.h",
     "navigation/navigation_item_impl.mm",
+    "navigation/navigation_item_storage_builder.h",
+    "navigation/navigation_item_storage_builder.mm",
     "navigation/navigation_manager_delegate.h",
     "navigation/navigation_manager_facade_delegate.h",
     "navigation/navigation_manager_impl.h",
@@ -97,6 +99,8 @@ source_set("web_arc") {
     "public/browser_url_rewriter.h",
     "public/cert_policy.h",
     "public/certificate_policy_cache.h",
+    "public/crw_navigation_item_storage.h",
+    "public/crw_navigation_item_storage.mm",
     "public/crw_navigation_manager_storage.h",
     "public/crw_navigation_manager_storage.mm",
     "public/favicon_status.cc",
@@ -514,6 +518,7 @@ test("ios_web_unittests") {
     "active_state_manager_impl_unittest.mm",
     "browser_state_unittest.cc",
     "history_state_util_unittest.mm",
+    "navigation/crw_navigation_item_storage_unittest.mm",
     "navigation/crw_session_controller_unittest.mm",
     "navigation/crw_session_entry_unittest.mm",
     "navigation/navigation_item_impl_unittest.mm",
@@ -546,6 +551,7 @@ test("ios_web_unittests") {
     "web_state/js/crw_js_post_request_loader_unittest.mm",
     "web_state/js/crw_js_window_id_manager_unittest.mm",
     "web_state/js/page_script_util_unittest.mm",
+    "web_state/page_display_state_unittest.mm",
     "web_state/ui/crw_web_controller_container_view_unittest.mm",
     "web_state/ui/crw_web_controller_observer_unittest.mm",
     "web_state/ui/crw_web_controller_unittest.mm",