WebUI: Disallow usages of obsolete Polymer() syntax via ESLint checks.

The class based "extends PolymerElement" syntax has been the preferred
way for a very long time and the vast majority of the codebase is
already using it.

Added a couple exceptions for a few CrOS folders that still use the old
syntax, and otherwise disallowing any new usages via ESLint's
no-restricted-imports rule.

All violations discovered with  the following command should have been
fixed or suppressed already.
git cl presubmit --files "*.js;*.ts"

Bug: 720034
Change-Id: I630dfbcfdbd1cab066e2faf145e6685ecb4693ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4412401
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Cole Horvitz <colehorvitz@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1128705}

.eslintrc.js

@@ -27,6 +27,18 @@ module.exports = {
     'no-extra-boolean-cast': 'error',
     'no-extra-semi': 'error',
     'no-new-wrappers': 'error',
+    'no-restricted-imports': ['error', {
+      'paths': [{
+        'name':  'chrome://resources/polymer/v3_0/polymer/polymer_bundled.min.js',
+        'importNames': ['Polymer'],
+        'message': 'Use PolymerElement instead.',
+      },
+      {
+        'name':  '//resources/polymer/v3_0/polymer/polymer_bundled.min.js',
+        'importNames': ['Polymer'],
+        'message': 'Use PolymerElement instead.',
+      }],
+    }],
     'no-restricted-properties': [
       'error',
       {

ash/webui/.eslintrc.js

@@ -6,5 +6,9 @@ module.exports = {
   'rules' : {
     'comma-dangle' : ['error', 'always-multiline'],
     'no-console' : 'off',
+
+    // Turn off since there are too many imports of 'Polymer'. Remove if/when
+    // everything under this folder is migrated to PolymerElement.
+    'no-restricted-imports' : 'off',
   },
 };

chrome/browser/resources/chromeos/.eslintrc.js

@@ -5,5 +5,9 @@
 module.exports = {
   'rules' : {
     'eqeqeq' : 'off',
+
+    // Turn off since there are too many imports of 'Polymer'. Remove if/when
+    // everything under this folder is migrated to PolymerElement.
+    'no-restricted-imports': 'off',
   },
 };

chrome/browser/resources/nearby_internals/.eslintrc.js

@@ -0,0 +1,11 @@
+// Copyright 2023 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module.exports = {
+  'rules' : {
+    // Remove if/when everything under this folder is migrated to
+    // PolymerElement.
+    'no-restricted-imports': 'off',
+  },
+};

ui/file_manager/file_manager/foreground/elements/.eslintrc.js

@@ -0,0 +1,11 @@
+// Copyright 2023 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module.exports = {
+  'rules' : {
+    // Turn off since there are many imports of 'Polymer'. Remove if/when
+    // everything under this folder is migrated to PolymerElement.
+    'no-restricted-imports': 'off',
+  },
+};