Non-SFI mode: Open primary IPC::Channel before seccomp-sandbox enabled.

components/nacl/loader/sandbox_linux/nacl_sandbox_linux.cc

Index: components/nacl/loader/sandbox_linux/nacl_sandbox_linux.cc
diff --git a/components/nacl/loader/sandbox_linux/nacl_sandbox_linux.cc b/components/nacl/loader/sandbox_linux/nacl_sandbox_linux.cc
index 869658f9f8b4eddec6efdd545b89c966626b0440..2e002184d16142c8fdce8620fcd9937ce9170f5a 100644
--- a/components/nacl/loader/sandbox_linux/nacl_sandbox_linux.cc
+++ b/components/nacl/loader/sandbox_linux/nacl_sandbox_linux.cc
@@ -148,18 +148,24 @@ void NaClSandbox::InitializeLayerOneSandbox() {
   }
 }
 
-void NaClSandbox::CheckForExpectedNumberOfOpenFds() {
+void NaClSandbox::CheckForExpectedNumberOfOpenFds(bool uses_nonsfi_mode) {
   // We expect to have the following FDs open:
   //  1-3) stdin, stdout, stderr.
   //  4) The /dev/urandom FD used by base::GetUrandomFD().
   //  5) A dummy pipe FD used to overwrite kSandboxIPCChannel.
   //  6) The socket for the Chrome IPC channel that's connected to the
   //     browser process, kPrimaryIPCChannel.
+  //
+  // In addition, in Non-SFI mode,
+  //  7-8) The socketpair dedicated for FD passing over 6)'s Chrome IPC
+  //     channel. CLIENT_MODE IPC channel needs to open them. One for the NaCl
+  //     loader side. The other will be sent to the browser process, after the
+  //     sandbox is engaged.
   // We also have an fd for /proc (proc_fd_), but CountOpenFds excludes this.
   //
   // This sanity check ensures that dynamically loaded libraries don't
   // leave any FDs open before we enable the sandbox.
-  int expected_num_fds = 6;
+  int expected_num_fds = uses_nonsfi_mode ? 8 : 6;
   if (setuid_sandbox_client_->IsSuidSandboxChild()) {
     // When using the setuid sandbox, there is one additional socket used for
     // ChrootMe(). After ChrootMe(), it is no longer connected to anything.
@@ -174,7 +180,7 @@ void NaClSandbox::InitializeLayerTwoSandbox(bool uses_nonsfi_mode) {
   // have a single thread running here.
   DCHECK(!layer_one_sealed_);
   CHECK(IsSingleThreaded());
-  CheckForExpectedNumberOfOpenFds();
+  CheckForExpectedNumberOfOpenFds(uses_nonsfi_mode);
 
   RestrictAddressSpaceUsage();