[NaCl SDK]: nacl_io: add nacl_io_uninit function.

Call this function on program shut down to allow
nacl_io to free its resources.  This fixes
all the "potential" leak reported by valgrind
--leak-check=full

Review URL: https://codereview.chromium.org/601963002

Cr-Commit-Position: refs/heads/master@{#296720}

native_client_sdk/src/libraries/nacl_io/nacl_io.cc

@@ -12,6 +12,10 @@ void nacl_io_init() {
   ki_init(NULL);
 }
 
+void nacl_io_uninit() {
+  ki_uninit();
+}
+
 void nacl_io_init_ppapi(PP_Instance instance, PPB_GetInterface get_interface) {
   ki_init_ppapi(NULL, instance, get_interface);
 }

native_client_sdk/src/libraries/nacl_io/nacl_io.h

@@ -51,6 +51,14 @@ void nacl_io_init();
  */
 void nacl_io_init_ppapi(PP_Instance instance, PPB_GetInterface get_interface);
 
+/**
+ * Uninitialize nacl_io.
+ *
+ * This removes interception for POSIX C-library function and releases
+ * any associated resources.
+ */
+void nacl_io_uninit();
+
 void nacl_io_set_exit_callback(nacl_io_exit_callback_t exit_callback,
                                void* user_data);
 

native_client_sdk/src/libraries/ppapi_simple/ps_main.cc

@@ -43,5 +43,7 @@ int main(int argc, char* argv[]) {
   // By default, or if not running in the browser we simply run the main
   // entry point directly, on the main thread.
   nacl_io_init();
-  return PSUserMainGet()(argc, argv);
+  int rtn = PSUserMainGet()(argc, argv);
+  nacl_io_uninit();
+  return rtn;
 }