[buildtools] Issue 4578 - Make uap3:AppExtension.Id configurable for Microsoft Edge builds

packagerEdge.py

 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 import base64
 import hashlib
 import json
 import mimetypes
 import os
 import zipfile
@@ skipping 69 matching lines @@
     """Create AppxManifest.xml."""
     params = dict(params)
     metadata = params['metadata']
     w = params['windows_version'] = {}
     w['min'], w['max'] = metadata.get('compat', 'windows').split('/')
     params.update(metadata.items('general'))
     params['version'] = pad_version(params['version'])
 
     metadata_id_suffix = 'release' if release_build else 'devbuild'
     metadata_id = 'extension_id_' + metadata_id_suffix
-    params['app_extension_id'] = metadata.get('general', metadata_id)
+    if metadata.has_option('general', metadata_id):
+        params['app_extension_id'] = metadata.get('general', metadata_id)
+    else:
+        params['app_extension_id'] = 'EdgeExtension'
 
     translation = load_translation(files, defaultLocale)
     name_key = 'name' if release_build else 'name_devbuild'
     params['display_name'] = translation[name_key]['message']
     params['description'] = translation['description']['message']
 
     for size in ['44', '50', '150']:
         path = '{}/logo_{}.png'.format(ASSETS_DIR, size)
         if path not in files:
             raise KeyError(path + ' is not found in files')
@@ skipping 84 matching lines @@
     if metadata.has_section('appx_assets'):
         for name, path in metadata.items('appx_assets'):
             path = os.path.join(baseDir, path)
             files.read(path, '{}/{}'.format(ASSETS_DIR, name))
 
     files[MANIFEST] = create_appx_manifest(params, files, releaseBuild)
     files[BLOCKMAP] = create_appx_blockmap(files)
     files[CONTENT_TYPES] = create_content_types_map(files.keys() + [BLOCKMAP])
 
     files.zip(outfile, compression=zipfile.ZIP_STORED)