Convert //ios from scoped_ptr to std::unique_ptr.

ios/web/shell/shell_web_main_parts.h

 // Copyright 2014 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 IOS_WEB_SHELL_SHELL_WEB_MAIN_PARTS_H_
 #define IOS_WEB_SHELL_SHELL_WEB_MAIN_PARTS_H_
 
+#include <memory>
+
 #include "ios/web/public/app/web_main_parts.h"
 
-#include "base/memory/scoped_ptr.h"
 
 namespace web {
 class ShellBrowserState;
 
 // Shell-specific implementation of WebMainParts.
 class ShellWebMainParts : public WebMainParts {
  public:
   ShellWebMainParts();
   ~ShellWebMainParts() override;
 
   ShellBrowserState* browser_state() const { return browser_state_.get(); }
 
   // WebMainParts implementation.
   void PreMainMessageLoopRun() override;
 
  private:
-  scoped_ptr<ShellBrowserState> browser_state_;
+  std::unique_ptr<ShellBrowserState> browser_state_;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_SHELL_SHELL_WEB_MAIN_PARTS_H_