Create a NavigationEntry for the initial blank page.

chrome/browser/ui/sync/tab_contents_synced_tab_delegate.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_SYNC_TAB_CONTENTS_SYNCED_TAB_DELEGATE_H_
 #define CHROME_BROWSER_UI_SYNC_TAB_CONTENTS_SYNCED_TAB_DELEGATE_H_
 
 #include "base/compiler_specific.h"
 #include "chrome/browser/sync/glue/synced_tab_delegate.h"
 #include "components/sessions/core/session_id.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace content {
 class WebContents;
 }
 
 class TabContentsSyncedTabDelegate
     : public browser_sync::SyncedTabDelegate,
       public content::WebContentsUserData<TabContentsSyncedTabDelegate> {
  public:
   ~TabContentsSyncedTabDelegate() override;
 
   // Methods from SyncedTabDelegate.
   SessionID::id_type GetWindowId() const override;
   SessionID::id_type GetSessionId() const override;
   bool IsBeingDestroyed() const override;
   Profile* profile() const override;
   std::string GetExtensionAppId() const override;
+  bool IsInitialBlankNavigation() const override;
   int GetCurrentEntryIndex() const override;
   int GetEntryCount() const override;
   int GetPendingEntryIndex() const override;
   content::NavigationEntry* GetPendingEntry() const override;
   content::NavigationEntry* GetEntryAtIndex(int i) const override;
   content::NavigationEntry* GetActiveEntry() const override;
   bool ProfileIsSupervised() const override;
   const std::vector<const content::NavigationEntry*>* GetBlockedNavigations()
       const override;
   bool IsPinned() const override;
   bool HasWebContents() const override;
   content::WebContents* GetWebContents() const override;
   int GetSyncId() const override;
   void SetSyncId(int sync_id) override;
 
  private:
   explicit TabContentsSyncedTabDelegate(content::WebContents* web_contents);
   friend class content::WebContentsUserData<TabContentsSyncedTabDelegate>;
 
   content::WebContents* web_contents_;
   int sync_session_id_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContentsSyncedTabDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_SYNC_TAB_CONTENTS_SYNCED_TAB_DELEGATE_H_