Convert HandoffActiveURLObserver to use the new navigation callbacks.

chrome/browser/ui/cocoa/handoff_active_url_observer.h

Index: chrome/browser/ui/cocoa/handoff_active_url_observer.h
diff --git a/chrome/browser/ui/cocoa/handoff_active_url_observer.h b/chrome/browser/ui/cocoa/handoff_active_url_observer.h
index 9a8dfac8c6f2cff108047b987303cfccf076f352..e0ee1ea091b948501079d02a4d78ee3c6698c95a 100644
--- a/chrome/browser/ui/cocoa/handoff_active_url_observer.h
+++ b/chrome/browser/ui/cocoa/handoff_active_url_observer.h
@@ -39,9 +39,8 @@ class HandoffActiveURLObserver : public chrome::BrowserListObserver,
                         int reason) override;
 
   // content::WebContentsObserver
-  void DidNavigateMainFrame(
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override;
+  void DidFinishNavigation(
+      content::NavigationHandle* navigation_handle) override;
 
   // Updates the active browser.
   void SetActiveBrowser(Browser* active_browser);