Set up NaClChromeMainArgs number_of_cores member so apps can size threadpools appropriately

chrome/nacl/nacl_listener.h

Index: chrome/nacl/nacl_listener.h
diff --git a/chrome/nacl/nacl_listener.h b/chrome/nacl/nacl_listener.h
index 20e3e7837e3a58076a8b37d8d55006219a67de1f..66627c0f6a9f6bdd23609f7627844026f8073640 100644
--- a/chrome/nacl/nacl_listener.h
+++ b/chrome/nacl/nacl_listener.h
@@ -34,6 +34,11 @@ class NaClListener : public IPC::Listener {
     prereserved_sandbox_size_ = prereserved_sandbox_size;
   }
 #endif
+#if defined(OS_POSIX)
+  void set_number_of_cores(int number_of_cores) {
+    number_of_cores_ = number_of_cores;
+  }
+#endif
 
  private:
   void OnStart(const nacl::NaClStartParams& params);
@@ -51,6 +56,16 @@ class NaClListener : public IPC::Listener {
 #if defined(OS_LINUX)
   size_t prereserved_sandbox_size_;
 #endif
+#if defined(OS_POSIX)
+  /*
+   * The outer sandbox on Linux and OSX prevents
+   * sysconf(_SC_NPROCESSORS) from working; in Windows, there are no
+   * problems with invoking GetSystemInfo.  Therefore, only in
+   * OS_POSIX do we need to supply the number of cores into
+   * NaClChromeMainArgs object.
+   */
+  int number_of_cores_;
+#endif
 
   // Used to identify what thread we're on.
   MessageLoop* main_loop_;