Enable Javascript formatting by default

This removes the need for explicitly passing `--js` to `git cl format`
to format both JavaScript and TypeScript. It would reduce a significant
amount of mental overhead for formatting code in DevTools frontend,
which is primarily JS/TS.

Fixed: 1007347
Change-Id: Ia35c9af677d12ce9be72fe5fcdd6ceb6cb039c5f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2029371
Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>

git_cl.py

@@ -5234,8 +5234,15 @@ def CMDformat(parser, args):
   parser.add_option(
       '--js',
       action='store_true',
+      default=None,
       help='Format javascript code with clang-format. '
       'Has no effect if --no-clang-format is set.')
+  parser.add_option(
+      '--no-js',
+      action='store_true',
+      default=False,
+      help='Disable JavaScript/TypeScript formatting code with clang-format. '
+      'Has no effect if --no-clang-format is set.')
   parser.add_option('--diff', action='store_true',
                     help='Print diff to stdout rather than modifying files.')
   parser.add_option('--presubmit', action='store_true',
@@ -5246,6 +5253,10 @@ def CMDformat(parser, args):
     raise parser.error('Cannot set both --python and --no-python')
   if opts.no_python:
     opts.python = False
+  if opts.js is not None and opts.no_js:
+    raise parser.error('Cannot set both --js and --no-js')
+  if opts.no_js:
+    opts.js = False
 
   # Normalize any remaining args against the current path, so paths relative to
   # the current directory are still resolved as expected.
@@ -5278,7 +5289,8 @@ def CMDformat(parser, args):
   # Filter out files deleted by this CL
   diff_files = [x for x in diff_files if os.path.isfile(x)]
 
-  if opts.js:
+  js_explicitly_disabled = opts.js is not None and not opts.js
+  if not js_explicitly_disabled:
     CLANG_EXTS.extend(['.js', '.ts'])
 
   clang_diff_files = []