app-shell: Introduce a ShellRendererMainDelegate.

apps/shell/app/shell_main_delegate.cc

Index: apps/shell/app/shell_main_delegate.cc
diff --git a/apps/shell/app/shell_main_delegate.cc b/apps/shell/app/shell_main_delegate.cc
index b8f835d1ae84a3e6177c0afabded275a1b090ed9..eab68a4dfebb96dc63a6dcf65111afe799f99b1e 100644
--- a/apps/shell/app/shell_main_delegate.cc
+++ b/apps/shell/app/shell_main_delegate.cc
@@ -73,7 +73,8 @@ content::ContentBrowserClient* ShellMainDelegate::CreateContentBrowserClient() {
 
 content::ContentRendererClient*
 ShellMainDelegate::CreateContentRendererClient() {
-  renderer_client_.reset(new ShellContentRendererClient);
+  renderer_client_.reset(
+      new ShellContentRendererClient(CreateShellRendererMainDelegate()));
   return renderer_client_.get();
 }
 
@@ -81,6 +82,11 @@ ShellBrowserMainDelegate* ShellMainDelegate::CreateShellBrowserMainDelegate() {
   return new DefaultShellBrowserMainDelegate();
 }
 
+ShellRendererMainDelegate*
+ShellMainDelegate::CreateShellRendererMainDelegate() {
+  return NULL;
+}
+
 // static
 bool ShellMainDelegate::ProcessNeedsResourceBundle(
     const std::string& process_type) {