Convert WebContentsModalDialogManager to use the new navigation callbacks.

components/web_modal/web_contents_modal_dialog_manager.h

Index: components/web_modal/web_contents_modal_dialog_manager.h
diff --git a/components/web_modal/web_contents_modal_dialog_manager.h b/components/web_modal/web_contents_modal_dialog_manager.h
index 9d964d1c4edc46fdf58cac519245bf22759850fc..bd3f5e0e0fa743c95cf1afbb9742a55173b32c85 100644
--- a/components/web_modal/web_contents_modal_dialog_manager.h
+++ b/components/web_modal/web_contents_modal_dialog_manager.h
@@ -100,9 +100,8 @@ class WebContentsModalDialogManager
   void CloseAllDialogs();
 
   // Overridden from content::WebContentsObserver:
-  void DidNavigateMainFrame(
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override;
+  void DidFinishNavigation(
+      content::NavigationHandle* navigation_handle) override;
   void DidGetIgnoredUIEvent() override;
   void WasShown() override;
   void WasHidden() override;