Move desktop-related code to "desktop" subfolder (#872)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/872
Move all the JS code related to desktop app to "desktop" subfolder.

The structure of "desktop" folder:
- `src` - JS code of Flipper desktop app executing in Electron Renderer (Chrome) process. This folder also contains all the Flipper plugins in subfolder "src/plugins".
- `static` - JS code of Flipper desktop app bootstrapping executing in Electron Main (Node.js) process
- `pkg` - Flipper packaging lib and CLI tool
- `doctor` - Flipper diagnostics lib and CLI tool
- `scripts` - Build scripts for Flipper desktop app
- `headless` - Headless version of Flipper app
- `headless-tests` - Integration tests running agains Flipper headless version

Reviewed By: passy

Differential Revision: D20249304

fbshipit-source-id: 9a51c63b51b92b758a02fc8ebf7d3d116770efe9

desktop/static/transforms/electron-requires.js

@@ -0,0 +1,94 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+const BUILTINS = [
+  'electron',
+  'buffer',
+  'child_process',
+  'crypto',
+  'dgram',
+  'dns',
+  'fs',
+  'http',
+  'https',
+  'net',
+  'os',
+  'readline',
+  'stream',
+  'string_decoder',
+  'tls',
+  'tty',
+  'zlib',
+  'constants',
+  'events',
+  'url',
+  'assert',
+  'util',
+  'path',
+  'perf_hooks',
+  'punycode',
+  'querystring',
+  'cluster',
+  'console',
+  'module',
+  'process',
+  'vm',
+  'domain',
+  'v8',
+  'repl',
+  'timers',
+  'node-fetch',
+];
+
+const IGNORED_MODULES = [
+  'bufferutil',
+  'utf-8-validate',
+  'spawn-sync',
+  './src/logcat',
+  './src/monkey',
+  './src/adb',
+];
+
+function isRequire(node) {
+  return (
+    node.type === 'CallExpression' &&
+    node.callee.type === 'Identifier' &&
+    node.callee.name === 'require' &&
+    node.arguments.length === 1 &&
+    node.arguments[0].type === 'StringLiteral'
+  );
+}
+
+module.exports = function(babel) {
+  const t = babel.types;
+
+  return {
+    name: 'infinity-import-react',
+    visitor: {
+      CallExpression(path) {
+        if (!isRequire(path.node)) {
+          return;
+        }
+
+        const source = path.node.arguments[0].value;
+
+        if (
+          BUILTINS.includes(source) ||
+          BUILTINS.some(moduleName => source.startsWith(`${moduleName}/`))
+        ) {
+          path.node.callee.name = 'electronRequire';
+        }
+
+        if (IGNORED_MODULES.includes(source)) {
+          path.replaceWith(t.identifier('triggerReferenceError'));
+        }
+      },
+    },
+  };
+};