DevTools: check BUILD.gn file as part of PRESUBMIT

third_party/WebKit/Source/devtools/scripts/check_gn.js

Index: third_party/WebKit/Source/devtools/scripts/check_gn.js
diff --git a/third_party/WebKit/Source/devtools/scripts/check_gn.js b/third_party/WebKit/Source/devtools/scripts/check_gn.js
new file mode 100644
index 0000000000000000000000000000000000000000..f46e72ca2d733e1d6d615b9ad048e8a3ff2b1d2b
--- /dev/null
+++ b/third_party/WebKit/Source/devtools/scripts/check_gn.js
@@ -0,0 +1,65 @@
+// 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.
+
+const fs = require('fs');
+const path = require('path');
+
+const inspectorManifest = require('../front_end/inspector.json');
+const utils = require('./utils');
+
+const gnPath = path.resolve(__dirname, '..', 'BUILD.gn');
+const gnFile = fs.readFileSync(gnPath, 'utf-8');
+const gnLines = gnFile.split('\n');
+
+function main() {
+  let errors = [];
+  errors = errors.concat(checkNonAutostartNonRemoteModules());
+  if (errors.length) {
+    console.log('DevTools BUILD.gn checker detected errors!');
+    console.log(`There's an issue with: ${gnPath}`);
+    console.log(errors.join('\n'));
+    process.exit(1);
+  }
+  console.log('DevTools BUILD.gn checker passed');
+}
+
+main();
+
+function checkNonAutostartNonRemoteModules() {
+  const errors = [];
+  const gnVariable = 'generated_non_autostart_non_remote_modules';
+  const lines = selectGNLines(`${gnVariable} = [`, ']');
+  if (!lines.length) {
+    return [
+      'Could not identify non-autostart non-remote modules in gn file',
+      'Please look at: ' + __filename,
+    ];
+  }
+  const text = lines.join('\n');
+  const modules = inspectorManifest.modules.filter(m => m.type !== 'autostart' && m.type !== 'remote').map(m => m.name);
+
+  const missingModules = modules.filter(m => !utils.includes(text, `${m}/${m}_module.js`));
+  if (missingModules.length)
+    errors.push(`Check that you've included [${missingModules.join(', ')}] modules in: ` + gnVariable);
+
+  // e.g. "$resources_out_dir/audits/audits_module.js" => "audits"
+  const mapLineToModuleName = line => line.split('/')[2].split('_module')[0];
+
+  const extraneousModules = lines.map(mapLineToModuleName).filter(module => !utils.includes(modules, module));
+  if (extraneousModules.length)
+    errors.push(`Found extraneous modules [${extraneousModules.join(', ')}] in: ` + gnVariable);
+
+  return errors;
+}
+
+function selectGNLines(startLine, endLine) {
+  let lines = gnLines.map(line => line.trim());
+  let startIndex = lines.indexOf(startLine);
+  if (startIndex === -1)
+    return [];
+  let endIndex = lines.indexOf(endLine, startIndex);
+  if (endIndex === -1)
+    return [];
+  return lines.slice(startIndex + 1, endIndex);
+}