Revert of Change net's predictor_tab_helper to use the new content Navigation API

chrome/browser/net/predictor_tab_helper.h

Index: chrome/browser/net/predictor_tab_helper.h
diff --git a/chrome/browser/net/predictor_tab_helper.h b/chrome/browser/net/predictor_tab_helper.h
index 355d711c30052a29edabdefe719da18951d08f3a..4d95ba0d2b56d9635856a557fda4c1ae320d74a9 100644
--- a/chrome/browser/net/predictor_tab_helper.h
+++ b/chrome/browser/net/predictor_tab_helper.h
@@ -11,10 +11,6 @@
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
-namespace content {
-class NavigationHandle;
-}
-
 namespace chrome_browser_net {
 
 class PredictorTabHelper
@@ -23,9 +19,7 @@
  public:
   ~PredictorTabHelper() override;
 
-  // content::WebContentsObserver:
-  void DidStartNavigation(
-      content::NavigationHandle* navigation_handle) override;
+  // content::WebContentsObserver implementation
   void DidStartNavigationToPendingEntry(
       const GURL& url,
       content::NavigationController::ReloadType reload_type) override;
@@ -34,8 +28,6 @@
   explicit PredictorTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<PredictorTabHelper>;
 
-  void PreconnectUrl(const GURL& url);
-
   DISALLOW_COPY_AND_ASSIGN(PredictorTabHelper);
 };