Allow node.py to run any node script

In DevTools, we want to write Node scripts as part of our Ninja action
scripts. That's because we are more familiar with Node than with Python.
However, since Ninja only allows Python scripts to be a script of an
`action`, we were previously forced to write Python.

This change allows the `third_party/node/node.py` script to be used as
if it was a regular `node <script args>` invocation. As a result, we can
use this script as part of a Ninja action as follows:

```
action(target_name) {
  script = "//third_party/node/node.py"

  args = [
    "path/to/my/node/script.js",
    "--any-arg",
    anyValueForArg,
  ]
}
```

We were previously already using this in DevTools itself, but that
requires a Node checkout in
`third_party/devtools-frontend/src/third_party/node`. To make sure that
a build in Chromium is possible as well, we need to reference the
absolute path to `//third_party/node/node.py` and thus requires the same
file to exist in Chromium itself.

Additionally, the script would now fail with the exitcode as defined by
the invoked Node script.

Lastly, this CL reformats the script according to the Python formatting
standard.

Bug: 1096473

R=jacktfranklin@chromium.org,dpapad@chromium.org
CC=​devtools-reviews+blink@chromium.org

Change-Id: Ie11150475d4d32c9dc9e8ec18228d490239ff7c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2248568Reviewed-by: dpapad <dpapad@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#780723}

chrome/browser/resources/optimize_webui.py

@@ -105,7 +105,7 @@ for (redirect_url, file_path) in [
 
 
 _VULCANIZE_REDIRECT_ARGS = list(itertools.chain.from_iterable(map(
-    lambda m: ['--redirect', '"%s|%s"' % (m[0], m[1])], _URL_MAPPINGS)))
+    lambda m: ['--redirect', '%s|%s' % (m[0], m[1])], _URL_MAPPINGS)))
 
 
 def _undo_mapping(mappings, url):
@@ -191,7 +191,7 @@ def _generate_manifest_file(tmp_out_dir, in_path, manifest_out_path):
       replaced_sources = []
       for source in sources:
         replaced_sources.append(
-            source.replace('../' + os.path.basename(in_path) + "/", ""))
+            source.replace('../' + os.path.basename(in_path) + '/', ''))
       filename = sourcemap_file[:-len('.map')]
       manifest[os.path.basename(filename)] = replaced_sources
       output_filenames.append(filename)
@@ -271,7 +271,7 @@ def _bundle_v2(tmp_out_dir, in_path, out_path, manifest_out_path, args,
       [
        '--manifest-out', manifest_out_path,
        '--root', in_path,
-       '--redirect', '"chrome://%s/|%s"' % (args.host, in_path + '/'),
+       '--redirect', 'chrome://%s/|%s' % (args.host, in_path + '/'),
        '--out-dir', os.path.relpath(tmp_out_dir, _CWD).replace('\\', '/'),
        '--shell', args.html_in_files[0],
       ] + in_html_args)
@@ -349,7 +349,7 @@ def _optimize(in_folder, args):
     for index, js_out_file in enumerate(args.js_out_files):
       node.RunNode([node_modules.PathToUglify(),
                     os.path.join(tmp_out_dir, js_out_file),
-                    '--comments', '"/Copyright|license|LICENSE|\<\/?if/"',
+                    '--comments', '/Copyright|license|LICENSE|\<\/?if/',
                     '--output', os.path.join(out_path, js_out_file)])
   finally:
     shutil.rmtree(tmp_out_dir)

third_party/node/node.py

@@ -7,23 +7,34 @@ from os import path as os_path
 import platform
 import subprocess
 import sys
+import os
 
 
 def GetBinaryPath():
-  return os_path.join(os_path.dirname(__file__), *{
-    'Darwin': ('mac', 'node-darwin-x64', 'bin', 'node'),
-    'Linux': ('linux', 'node-linux-x64', 'bin', 'node'),
-    'Windows': ('win', 'node.exe'),
-  }[platform.system()])
+    return os_path.join(
+        os_path.dirname(__file__), *{
+            'Darwin': ('mac', 'node-darwin-x64', 'bin', 'node'),
+            'Linux': ('linux', 'node-linux-x64', 'bin', 'node'),
+            'Windows': ('win', 'node.exe'),
+        }[platform.system()])
 
 
 def RunNode(cmd_parts, stdout=None):
-  cmd = " ".join([GetBinaryPath()] + cmd_parts)
-  process = subprocess.Popen(
-      cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
-  stdout, stderr = process.communicate()
+    cmd = [GetBinaryPath()] + cmd_parts
+    # Pipe the output, because in Ninja actions we don't want
+    # to print any output, unless the action failed.
+    process = subprocess.Popen(cmd,
+                               cwd=os.getcwd(),
+                               stdout=subprocess.PIPE,
+                               stderr=subprocess.PIPE)
+    stdout, stderr = process.communicate()
 
-  if stderr:
-    raise RuntimeError('%s failed: %s' % (cmd, stderr))
+    if process.returncode != 0:
+        print('%s failed:\n%s' % (cmd, stdout + stderr))
+        exit(process.returncode)
 
-  return stdout
+    return stdout
+
+
+if __name__ == '__main__':
+    RunNode(sys.argv[1:])