skia2/infra/bots/assets/emscripten_sdk
..
common.py
create_and_upload.py
download.py
README.md
upload.py
VERSION

Checkout and build the emscripten_sdk following the instructions here: http://webassembly.org/getting-started/developers-guide/

Then, run infra/bots/assets/emscripten_sdk/create_and_upload.py -s /path/to/dir/emsdk

It will take a while because the emsdk dir is > 26GB.