Add support for Brotli decompression

For now, `BrotliDecode` hasn't been specified but it should be in a
close future.
So when it's possible we use the native `DecompressionStream` API
with "brotli" as argument.
If that fails or if we've to decompress in a sync context, we fallback
to `BrotliStream` which a pure js implementation (see README in external/brotli).

Author: calixteman

eslint.config.mjs

@@ -31,6 +31,7 @@ export default [
       "**/docs/",
       "**/node_modules/",
       "external/bcmaps/",
+      "external/brotli/",
       "external/builder/fixtures/",
       "external/builder/fixtures_babel/",
       "external/openjpeg/",

external/brotli/LICENSE_BROTLI

@@ -0,0 +1,19 @@
+Copyright (c) 2009, 2010, 2013-2016 by the Brotli Authors.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

external/brotli/README.md

@@ -0,0 +1,8 @@
+## Release
+
+In order to get the file `decoder.js`:
+* `gulp release-brotli --hash` followed by the git hash of the revision.
+
+## Licensing
+
+[brotli](https://github.com/google/brotli/) is under [MIT License](https://github.com/google/brotli/blob/master/LICENSE)