Add a debug view to the browser that allows various navigation features to be used.

services/navigation/view_impl.h

 // Copyright 2016 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 SERVICES_NAVIGATION_VIEW_IMPL_H_
 #define SERVICES_NAVIGATION_VIEW_IMPL_H_
 
 #include "base/macros.h"
 #include "components/mus/public/cpp/window_tree_client_delegate.h"
 #include "content/public/browser/web_contents_delegate.h"
@@ skipping 26 matching lines @@
 
  private:
   // mojom::View:
   void NavigateTo(const GURL& url) override;
   void GoBack() override;
   void GoForward() override;
   void Reload(bool skip_cache) override;
   void Stop() override;
   void GetWindowTreeClient(
       mus::mojom::WindowTreeClientRequest request) override;
+  void ShowInterstitial(const mojo::String& html) override;
+  void HideInterstitial() override;
 
   // content::WebContentsDelegate:
   void AddNewContents(content::WebContents* source,
                       content::WebContents* new_contents,
                       WindowOpenDisposition disposition,
                       const gfx::Rect& initial_rect,
                       bool user_gesture,
                       bool* was_blocked) override;
   void CloseContents(content::WebContents* source) override;
   void LoadingStateChanged(content::WebContents* source,
@@ skipping 23 matching lines @@
   std::unique_ptr<content::WebContents> web_contents_;
 
   std::unique_ptr<views::Widget> widget_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewImpl);
 };
 
 }  // navigation
 
 #endif  // SERVICES_NAVIGATION_VIEW_IMPL_H_