Plumbing though mode parameter to open, since fusefs can make use of it.

native_client_sdk/src/libraries/nacl_io/jsfs/js_fs.cc

Index: native_client_sdk/src/libraries/nacl_io/jsfs/js_fs.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/jsfs/js_fs.cc b/native_client_sdk/src/libraries/nacl_io/jsfs/js_fs.cc
index b0f18a5327c200aa15f0c28cb6864b064c2add5a..26d2e14e99919a4322d224eeb4b15d9bbb94c270 100644
--- a/native_client_sdk/src/libraries/nacl_io/jsfs/js_fs.cc
+++ b/native_client_sdk/src/libraries/nacl_io/jsfs/js_fs.cc
@@ -391,7 +391,8 @@ PP_Var JsFs::WaitForResponse(RequestId request_id) {
   }
 }
 
-Error JsFs::Open(const Path& path, int open_flags, ScopedNode* out_node) {
+Error JsFs::OpenWithMode(const Path& path, int open_flags, mode_t t,
+                         ScopedNode* out_node) {
   out_node->reset(NULL);
   ScopedVar response(ppapi_);
   if (!SendRequestAndWait(&response, "%s%s%d",