[Navigation Experiment] Add WKBasedNavigationManagerImpl.

ios/web/web_state/ui/crw_web_controller.mm

Index: ios/web/web_state/ui/crw_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_web_controller.mm b/ios/web/web_state/ui/crw_web_controller.mm
index 61ee232486bd3e1dae3e6285d49e8aae9157208e..8a046e57c51613ebcb611f49cd0ce9c8d6b1f35f 100644
--- a/ios/web/web_state/ui/crw_web_controller.mm
+++ b/ios/web/web_state/ui/crw_web_controller.mm
@@ -91,6 +91,7 @@
 #import "ios/web/web_state/ui/crw_web_view_proxy_impl.h"
 #import "ios/web/web_state/ui/crw_wk_navigation_states.h"
 #import "ios/web/web_state/ui/crw_wk_script_message_router.h"
+#import "ios/web/web_state/ui/web_view_navigation_proxy_impl.h"
 #import "ios/web/web_state/ui/wk_back_forward_list_item_holder.h"
 #import "ios/web/web_state/ui/wk_web_view_configuration_provider.h"
 #import "ios/web/web_state/web_controller_observer_bridge.h"
@@ -267,6 +268,7 @@ NSError* WKWebViewErrorWithSource(NSError* error, WKWebViewErrorSource source) {
   base::WeakNSProtocol<id<CRWSwipeRecognizerProvider>> _swipeRecognizerProvider;
   // The WKWebView managed by this instance.
   base::scoped_nsobject<WKWebView> _webView;
+  std::unique_ptr<web::WebViewNavigationProxyImpl> _webViewNavigationProxyImpl;
   // The CRWWebViewProxy is the wrapper to give components access to the
   // web view in a controlled and limited way.
   base::scoped_nsobject<CRWWebViewProxyImpl> _webViewProxy;
@@ -961,6 +963,8 @@ const NSTimeInterval kSnapshotOverlayTransition = 0.5;
            selector:@selector(orientationDidChange)
                name:UIApplicationDidChangeStatusBarOrientationNotification
              object:nil];
+    _webViewNavigationProxyImpl =
+        base::MakeUnique<web::WebViewNavigationProxyImpl>(nullptr);
   }
   return self;
 }
@@ -1425,6 +1429,11 @@ const NSTimeInterval kSnapshotOverlayTransition = 0.5;
   return _webViewProxy.get();
 }
 
+- (web::WebViewNavigationProxy*)webViewNavigationProxy {
+  _webViewNavigationProxyImpl->SetWebView(_webView);
+  return _webViewNavigationProxyImpl.get();
+}
+
 - (UIView*)viewForPrinting {
   // Printing is not supported for native controllers.
   return _webView;