[Navigation Experiment] Add WKBasedNavigationManagerImpl.

ios/web/navigation/navigation_manager_impl.h

Index: ios/web/navigation/navigation_manager_impl.h
diff --git a/ios/web/navigation/navigation_manager_impl.h b/ios/web/navigation/navigation_manager_impl.h
index 92f7fbb9def3a5cb967d6c3d28eb7c669b060769..318741d0f179bff2506f0af575b20d46df3d8281 100644
--- a/ios/web/navigation/navigation_manager_impl.h
+++ b/ios/web/navigation/navigation_manager_impl.h
@@ -137,6 +137,11 @@ class NavigationManagerImpl : public NavigationManager {
   // SessionStorageBuilder to persist session state.
   virtual NavigationItemImpl* GetNavigationItemImplAtIndex(
       size_t index) const = 0;
+
+  // Checks whether or not two URL are an in-page navigation (differing only
+  // in the fragment).
+  static bool AreURLsInPageNavigation(const GURL& existing_url,

[Eugene But (OOO till 7-30), 2017/06/29 01:48:19]

Could you please rename this to AreUrlsFragmentChangeNavigation

in-page is very confusing and can also mean pushState/replaceState.

[danyao, 2017/06/29 16:05:25]

Done.

+                                      const GURL& new_url);
 };
 
 }  // namespace web