[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..c703b7ca37b3bd03a8726136107435cbbec36085 100644
--- a/ios/web/web_state/ui/crw_web_controller.h
+++ b/ios/web/web_state/ui/crw_web_controller.h
@@ -6,7 +6,9 @@
 #define IOS_WEB_WEB_STATE_UI_CRW_WEB_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
+#import <WebKit/WebKit.h>
 
+#import "ios/web/navigation/web_view_navigation_proxy.h"
 #import "ios/web/net/crw_request_tracker_delegate.h"
 #import "ios/web/public/navigation_manager.h"
 #import "ios/web/public/web_state/js/crw_js_injection_evaluator.h"
@@ -74,6 +76,10 @@ 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)
+    web::WebViewNavigationProxy* webViewNavigationProxy;
+
 // The view that generates print data when printing. It is nil if printing
 // is not supported.
 @property(nonatomic, readonly) UIView* viewForPrinting;