Add a whitelist check for nacl-nonsfi mode

components/nacl/browser/nacl_process_host.cc

Index: components/nacl/browser/nacl_process_host.cc
diff --git a/components/nacl/browser/nacl_process_host.cc b/components/nacl/browser/nacl_process_host.cc
index f3c91a97ea7c22ca5bd137ac29c1e7bc11e06adf..29b194cdc0abe91d96f555ba405ffc04e6bc9a3d 100644
--- a/components/nacl/browser/nacl_process_host.cc
+++ b/components/nacl/browser/nacl_process_host.cc
@@ -27,6 +27,7 @@
 #include "base/win/windows_version.h"
 #include "build/build_config.h"
 #include "components/nacl/browser/nacl_browser.h"
+#include "components/nacl/browser/nacl_browser_delegate.h"
 #include "components/nacl/browser/nacl_host_message_filter.h"
 #include "components/nacl/common/nacl_cmd_line.h"
 #include "components/nacl/common/nacl_host_messages.h"
@@ -430,15 +431,18 @@ void NaClProcessHost::Launch(
   }
 
   if (uses_nonsfi_mode_) {
+    bool nonsfi_mode_enabled = false;
 #if defined(OS_LINUX)
-    const bool kNonSFIModeSupported = true;
-#else
-    const bool kNonSFIModeSupported = false;
+    nonsfi_mode_enabled = nonsfi_mode_enabled ||

[jln (very slow on Chromium), 2014/05/08 23:22:41]

This is fine, but if you don't mind havint different bools, I think it would
make this more readable for security:

#if... OS_LINUX
const bool non_sfi_mode_forced_by_command_line = cmd->..
# if defined(OS_CHROMEOS) && .. ARMEL)
const bool non_sfi_mode_allowed = ...->IsNonSfiModeAllowed);
#endif

nonsfi_mode_enabled = !non_sfi_mode_allowed &&
!non_sfi_mode_forced_by_command_line;

[jln (very slow on Chromium), 2014/05/08 23:44:57]

err, enabled, not disabled:

nonsfi_mode_enabled = non_sfi_mode_allowed ||
non_sfi_mode_forced_by_command_line;

[elijahtaylor1, 2014/05/09 00:33:28]

Done.

+        cmd->HasSwitch(switches::kEnableNaClNonSfiMode);
+# if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARMEL)
+    nonsfi_mode_enabled = nonsfi_mode_enabled ||
+        NaClBrowser::GetDelegate()->IsNonSfiModeAllowed(manifest_url_);
+# endif
 #endif
-    if (!kNonSFIModeSupported ||
-        !cmd->HasSwitch(switches::kEnableNaClNonSfiMode)) {
-      SendErrorToRenderer("NaCl non-SFI mode works only on Linux with"
-                          " --enable-nacl-nonsfi-mode specified");
+    if (!nonsfi_mode_enabled) {
+      SendErrorToRenderer("NaCl non-SFI mode is not available for this platform"
+                          " and NaCl module.");
       delete this;
       return;
     }