Open NaCl IRT file only once at startup

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 10a0a1f97ef46b8fe581a9597cea3204edbe366e..991387dfd276c2a28aa14e4ded122e52161fdcf7 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -52,6 +52,7 @@
 #include "chrome/browser/metrics/metrics_log.h"
 #include "chrome/browser/metrics/metrics_service.h"
 #include "chrome/browser/metrics/thread_watcher.h"
+#include "chrome/browser/nacl_host/nacl_process_host.h"
 #include "chrome/browser/net/chrome_dns_cert_provenance_checker.h"
 #include "chrome/browser/net/chrome_dns_cert_provenance_checker_factory.h"
 #include "chrome/browser/net/chrome_net_log.h"
@@ -1883,6 +1884,10 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunInternal() {
   // Start watching all browser threads for responsiveness.
   ThreadWatcherList::StartWatchingAll(parsed_command_line());
 
+#if !defined(DISABLE_NACL)
+  NaClProcessHost::OpenIrtLibraryFile();

[brettw, 2011/10/28 18:54:32]

You're doing blocking I/O on the UI thread blocking the startup path, which is
basically the worst thing you can do in Chrome. We need to get this onto a
background thread and I'd also like to do it lazily (since most people won't be
using NaCl at all, it's wasteful to open it every time).

[Elliot Glaysher, 2011/10/28 20:05:23]

Agreed. To interact with the package manager correctly, we need this as right
after we start up chrome, but we don't need to block the critical startup path
here. It can be a low priority file thread thing since we don't use nacl on the
ntp or anything.

This should kick off an asynchronous load (and probably on linux only) and then
keep that fd around.

+#endif
+
   int result_code = content::RESULT_CODE_NORMAL_EXIT;
   base::mac::ScopedNSAutoreleasePool* pool = parameters().autorelease_pool_;
   if (parameters().ui_task) {