Remove CWV class and move setting User Agent to CWVWebViewConfiguration.

ios/web_view/internal/web_view_web_main_delegate.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_VIEW_INTERNAL_WEB_VIEW_WEB_MAIN_DELEGATE_H_
 #define IOS_WEB_VIEW_INTERNAL_WEB_VIEW_WEB_MAIN_DELEGATE_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "ios/web/public/app/web_main_delegate.h"
 
 namespace ios_web_view {
 class WebViewWebClient;
 
 // WebView implementation of WebMainDelegate.
 class WebViewWebMainDelegate : public web::WebMainDelegate {
  public:
-  explicit WebViewWebMainDelegate(const std::string& user_agent_product);
+  WebViewWebMainDelegate();
   ~WebViewWebMainDelegate() override;
 
   // WebMainDelegate implementation.
   void BasicStartupComplete() override;
 
  private:
-  // The name of the product to be used in the User Agent string.
-  std::string user_agent_product_;
-
   // The content and web clients registered by this object.
   std::unique_ptr<WebViewWebClient> web_client_;
 
   DISALLOW_COPY_AND_ASSIGN(WebViewWebMainDelegate);
 };
 
 }  // namespace ios_web_view
 
 #endif  // IOS_WEB_VIEW_INTERNAL_WEB_VIEW_WEB_MAIN_DELEGATE_H_