[ios] Moved WebUI provider code to ios/web.

ios/chrome/browser/ui/webui/version_handler.h

 // Copyright 2015 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_CHROME_BROWSER_UI_WEBUI_VERSION_HANDLER_H_
 #define IOS_CHROME_BROWSER_UI_WEBUI_VERSION_HANDLER_H_
 
 #include "base/macros.h"
-#include "ios/public/provider/web/web_ui_ios_message_handler.h"
+#include "ios/web/public/webui/web_ui_ios_message_handler.h"
 
 namespace base {
 class ListValue;
 }
 
 // Handler class for Version page operations.
 class VersionHandler : public web::WebUIIOSMessageHandler {
  public:
   VersionHandler();
   ~VersionHandler() override;
 
   // content::WebUIMessageHandler implementation.
   void RegisterMessages() override;
 
   // Callback for the "requestVersionInfo" message. This asynchronously requests
   // the list of variations.
   void HandleRequestVersionInfo(const base::ListValue* args);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VersionHandler);
 };
 
 #endif  // IOS_CHROME_BROWSER_UI_WEBUI_VERSION_HANDLER_H_