Fix linux_chromeos_clang compile for app_shell

apps/shell/app_shell_browser_main_parts.cc

Index: apps/shell/app_shell_browser_main_parts.cc
diff --git a/apps/shell/app_shell_browser_main_parts.cc b/apps/shell/app_shell_browser_main_parts.cc
index c56918d47db34f8739d0b0ed06ca69725cdd1208..3cd7e799f3ec48623d1ff2bfa195568b18689a00 100644
--- a/apps/shell/app_shell_browser_main_parts.cc
+++ b/apps/shell/app_shell_browser_main_parts.cc
@@ -50,7 +50,7 @@ void AppShellBrowserMainParts::PreMainMessageLoopRun() {
   // window with a WebView just to ensure that the content module is properly
   // initialized.
   ShowWebViewWindow(browser_context_.get(),
-                    minimal_shell_->root_window());
+                    minimal_shell_->root_window()->window());
 }
 
 bool AppShellBrowserMainParts::MainMessageLoopRun(int* result_code)  {