[Navigation Experiment] Add WKBasedNavigationManagerImpl.

ios/web/web_state/ui/crw_web_controller.h

Index: ios/web/web_state/ui/crw_web_controller.h
diff --git a/ios/web/web_state/ui/crw_web_controller.h b/ios/web/web_state/ui/crw_web_controller.h
index a5d8c4df583252f3ae81655dfe3ff290944c0d22..19414da515af2c682bcc2f4e8eb52a83eb59343a 100644
--- a/ios/web/web_state/ui/crw_web_controller.h
+++ b/ios/web/web_state/ui/crw_web_controller.h
@@ -13,6 +13,7 @@
 #import "ios/web/public/web_state/ui/crw_web_delegate.h"
 #include "ios/web/public/web_state/url_verification_constants.h"
 #import "ios/web/web_state/ui/crw_touch_tracking_recognizer.h"
+#import "ios/web/web_state/ui/crw_web_view_navigation_proxy.h"
 
 namespace web {
 
@@ -74,6 +75,10 @@ class WebStateImpl;
 // The web view proxy associated with this controller.
 @property(nonatomic, readonly) id<CRWWebViewProxy> webViewProxy;
 
+// The web view navigation proxy associated with this controller.
+@property(nonatomic, readonly) id<CRWWebViewNavigationProxy>
+    webViewNavigationProxy;
+
 // The view that generates print data when printing. It is nil if printing
 // is not supported.
 @property(nonatomic, readonly) UIView* viewForPrinting;