Allow app_shell embedders to override extensions client interfaces

extensions/shell/renderer/shell_content_renderer_client.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 EXTENSIONS_SHELL_RENDERER_SHELL_CONTENT_RENDERER_CLIENT_H_
 #define EXTENSIONS_SHELL_RENDERER_SHELL_CONTENT_RENDERER_CLIENT_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/public/renderer/content_renderer_client.h"
 
 namespace extensions {
 
 class Dispatcher;
 class DispatcherDelegate;
-class ShellExtensionsClient;
+class ExtensionsClient;
 class ShellExtensionsRendererClient;
 class ShellRendererMainDelegate;
 
 // Renderer initialization and runtime support for app_shell.
 class ShellContentRendererClient : public content::ContentRendererClient {
  public:
   ShellContentRendererClient();
   ~ShellContentRendererClient() override;
 
   // content::ContentRendererClient implementation:
@@ skipping 17 matching lines @@
                               int extension_group,
                               int world_id) override;
   const void* CreatePPAPIInterface(const std::string& interface_name) override;
   bool IsExternalPepperPlugin(const std::string& module_name) override;
   bool ShouldEnableSiteIsolationPolicy() const override;
   content::BrowserPluginDelegate* CreateBrowserPluginDelegate(
       content::RenderFrame* render_frame,
       const std::string& mime_type,
       const GURL& original_url) override;
 
+ protected:
+  // app_shell embedders may need custom extensions client interfaces.
+  // This class takes ownership of the returned object.
+  virtual ExtensionsClient* CreateExtensionsClient();
+
  private:
-  scoped_ptr<ShellExtensionsClient> extensions_client_;
+  scoped_ptr<ExtensionsClient> extensions_client_;
   scoped_ptr<ShellExtensionsRendererClient> extensions_renderer_client_;
   scoped_ptr<DispatcherDelegate> extension_dispatcher_delegate_;
   scoped_ptr<Dispatcher> extension_dispatcher_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellContentRendererClient);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_SHELL_RENDERER_SHELL_CONTENT_RENDERER_CLIENT_H_