Create ExtensionsRendererClient.

apps/shell/renderer/shell_content_renderer_client.h

Index: apps/shell/renderer/shell_content_renderer_client.h
diff --git a/apps/shell/renderer/shell_content_renderer_client.h b/apps/shell/renderer/shell_content_renderer_client.h
index 4f31225c5b7dd7fa02e11dcf9bea2d1248e1f21a..4a34810ac8646ada93ec0cc6961b5630abe042fe 100644
--- a/apps/shell/renderer/shell_content_renderer_client.h
+++ b/apps/shell/renderer/shell_content_renderer_client.h
@@ -17,6 +17,7 @@ class Dispatcher;
 namespace apps {
 
 class ShellExtensionsClient;
+class ShellExtensionsRendererClient;
 
 // Renderer initialization and runtime support for app_shell.
 class ShellContentRendererClient : public content::ContentRendererClient {
@@ -41,6 +42,7 @@ class ShellContentRendererClient : public content::ContentRendererClient {
 
  private:
   scoped_ptr<ShellExtensionsClient> extensions_client_;
+  scoped_ptr<ShellExtensionsRendererClient> extensions_renderer_client_;
   scoped_ptr<extensions::Dispatcher> extension_dispatcher_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellContentRendererClient);