Consistently use notifications from component updater w/ on-demand PNaCl.

chrome/browser/nacl_host/nacl_browser_delegate_impl.cc

Index: chrome/browser/nacl_host/nacl_browser_delegate_impl.cc
diff --git a/chrome/browser/nacl_host/nacl_browser_delegate_impl.cc b/chrome/browser/nacl_host/nacl_browser_delegate_impl.cc
index 9e17b2f524ab2d7e71179aa08d858653043613ef..eec61e5188f97faa0d447fb9eb4e08c7e1b6f90b 100644
--- a/chrome/browser/nacl_host/nacl_browser_delegate_impl.cc
+++ b/chrome/browser/nacl_host/nacl_browser_delegate_impl.cc
@@ -61,8 +61,10 @@ ppapi::host::HostFactory* NaClBrowserDelegateImpl::CreatePpapiHostFactory(
 
 void NaClBrowserDelegateImpl::TryInstallPnacl(
     const base::Callback<void(bool)>& installed) {
-  ComponentUpdateService* cus = g_browser_process->component_updater();
   PnaclComponentInstaller* pci =
       g_browser_process->pnacl_component_installer();
-  RequestFirstInstall(cus, pci, installed);
+  if (pci)
+    pci->RequestFirstInstall(installed);
+  else
+    installed.Run(false);
 }