Delete the remove_stale_autogen_files mechanism.

Previously when moving around directories for generated files, Dawn ran
into an issue where stale files where #included instead of the new ones,
causing compilation failures. To get around this a
remove_stale_autogen_files mechanism was added that scans the gen/
directory for files not in an allow-list of directories.

This mechanism is now causing problems for bringing up Dawn standalone
tests on Android as these test also generate files in Dawn's gen/
directories, and their files get deleted by remove_stale_autogen_files.

We are not foresseing any additional shuffling of directories and it's
safe to expect that all stale files have been removed from CI builder
caches at this time. So remove_stale_autogen_files can go. This is what
this CL does.

Fixed: dawn:1543
Change-Id: I7dbf1eae6c55b7659f3837b6d4a565052001ce57
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/103040
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

generator/generator_lib.py

@@ -258,12 +258,6 @@ def run_generator(generator):
         type=str,
         help=('Optional source root directory for Python dependency '
               'computations'))
-    parser.add_argument(
-        '--allowed-output-dirs-file',
-        default=None,
-        type=str,
-        help=("File containing a list of allowed directories where files "
-              "can be output."))
     parser.add_argument(
         '--print-cmake-dependencies',
         default=False,
@@ -326,32 +320,6 @@ def run_generator(generator):
 
     outputs = _do_renders(renders, args.template_dir)
 
-    # The caller wants to assert that the outputs are only in specific
-    # directories.
-    if args.allowed_output_dirs_file != None:
-        with open(args.allowed_output_dirs_file) as f:
-            allowed_dirs = set([line.strip() for line in f.readlines()])
-
-        for directory in allowed_dirs:
-            if not directory.endswith('/'):
-                print('Allowed directory entry "{}" doesn\'t '
-                      'end with /'.format(directory))
-                return 1
-
-        def check_in_subdirectory(path, directory):
-            return path.startswith(
-                directory) and not '/' in path[len(directory):]
-
-        for render in renders:
-            if not any(
-                    check_in_subdirectory(render.output, directory)
-                    for directory in allowed_dirs):
-                print('Output file "{}" is not in the allowed directory '
-                      'list below:'.format(render.output))
-                for directory in sorted(allowed_dirs):
-                    print('    "{}"'.format(directory))
-                return 1
-
     # Output the JSON tarball
     if args.output_json_tarball != None:
         json_root = {}