Convert ExtensionViewGuest to use the new navigation callbacks.

extensions/browser/guest_view/extension_view/extension_view_guest.h

Index: extensions/browser/guest_view/extension_view/extension_view_guest.h
diff --git a/extensions/browser/guest_view/extension_view/extension_view_guest.h b/extensions/browser/guest_view/extension_view/extension_view_guest.h
index d947b240cc7e1ece15ab1e6ef9a109dd98ad4d8b..fc244e4817882d51be5d2415f35c852feac4f2a4 100644
--- a/extensions/browser/guest_view/extension_view/extension_view_guest.h
+++ b/extensions/browser/guest_view/extension_view/extension_view_guest.h
@@ -37,12 +37,7 @@ class ExtensionViewGuest
   int GetTaskPrefix() const final;
 
   // content::WebContentsObserver implementation.
-  void DidCommitProvisionalLoadForFrame(
-      content::RenderFrameHost* render_frame_host,
-      const GURL& url,
-      ui::PageTransition transition_type) final;
-  void DidNavigateMainFrame(const content::LoadCommittedDetails& details,
-                            const content::FrameNavigateParams& params) final;
+  void DidFinishNavigation(content::NavigationHandle* navigation_handle) final;
 
   // Applies attributes to the extensionview.
   void ApplyAttributes(const base::DictionaryValue& params);