WebUI: Add helper scripts for referring to node and node_modules paths.

third_party/node/node.py

+#!/usr/bin/env python
+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from os import path as os_path
+from platform import system as platform_system
+
+
+_THIRD_PARTY_NODE_DIR = os_path.join(os_path.dirname(__file__))
+
+# Gets the path to the Node binary based on current platform.
+def get_binary():
+  third_party_node_binary = '';
+
+  if platform_system() == 'Darwin':
+    third_party_node_binary = os_path.join(
+        'mac', 'node-darwin-x64', 'bin', 'node')
+  elif platform_system() == 'Linux':
+    third_party_node_binary = os_path.join(
+        'linux', 'node-linux-x64', 'bin', 'node')
+  elif platform_system() == 'Windows':
+    third_party_node_binary = os_path.join('win', 'node.exe')
+
+  return os_path.abspath(os_path.join(
+      _THIRD_PARTY_NODE_DIR, third_party_node_binary))