[Navigation Experiment] Add WKBasedNavigationManagerImpl.

ios/web/BUILD.gn

Index: ios/web/BUILD.gn
diff --git a/ios/web/BUILD.gn b/ios/web/BUILD.gn
index aca28f6888ce70779437bf5bb51d16ba8266f608..1d73e7d19078a3cc46d77500db136a6ed00e7d14 100644
--- a/ios/web/BUILD.gn
+++ b/ios/web/BUILD.gn
@@ -67,6 +67,7 @@ source_set("web_arc") {
     "navigation/navigation_item_storage_builder.mm",
     "navigation/navigation_manager_delegate.h",
     "navigation/navigation_manager_impl.h",
+    "navigation/navigation_manager_impl.mm",
     "navigation/navigation_manager_util.h",
     "navigation/navigation_manager_util.mm",
     "navigation/nscoder_util.h",
@@ -77,6 +78,8 @@ source_set("web_arc") {
     "navigation/session_storage_builder.mm",
     "navigation/time_smoother.cc",
     "navigation/time_smoother.h",
+    "navigation/wk_based_navigation_manager_impl.h",
+    "navigation/wk_based_navigation_manager_impl.mm",
     "net/cert_host_pair.cc",
     "net/cert_host_pair.h",
     "net/cert_policy.cc",
@@ -225,6 +228,9 @@ source_set("web_arc") {
     "web_state/ui/crw_web_view_scroll_view_proxy.mm",
     "web_state/ui/crw_wk_navigation_states.h",
     "web_state/ui/crw_wk_navigation_states.mm",
+    "web_state/ui/web_view_navigation_proxy.h",
+    "web_state/ui/web_view_navigation_proxy_impl.h",
+    "web_state/ui/web_view_navigation_proxy_impl.mm",
     "web_thread_impl.cc",
     "web_thread_impl.h",
     "web_view_creation_util.mm",