Use process/control messages (instead of RVH messages) for layout tests.

content/shell/app/shell_main_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 CONTENT_SHELL_APP_SHELL_MAIN_DELEGATE_H_
 #define CONTENT_SHELL_APP_SHELL_MAIN_DELEGATE_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "content/public/app/content_main_delegate.h"
+#include "content/shell/common/shell_content_client.h"
 
 namespace content {
 class ContentClient;
 class ShellContentBrowserClient;
 class ShellContentRendererClient;
 class ShellContentUtilityClient;
 
 #if defined(OS_ANDROID)
 class BrowserMainRunner;
 #endif
@@ skipping 14 matching lines @@
   ContentBrowserClient* CreateContentBrowserClient() override;
   ContentRendererClient* CreateContentRendererClient() override;
   ContentUtilityClient* CreateContentUtilityClient() override;
 
   static void InitializeResourceBundle();
 
  private:
   std::unique_ptr<ShellContentBrowserClient> browser_client_;
   std::unique_ptr<ShellContentRendererClient> renderer_client_;
   std::unique_ptr<ShellContentUtilityClient> utility_client_;
-  std::unique_ptr<ContentClient> content_client_;
+  ShellContentClient content_client_;
 
 #if defined(OS_ANDROID)
   std::unique_ptr<BrowserMainRunner> browser_runner_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ShellMainDelegate);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_APP_SHELL_MAIN_DELEGATE_H_