Devtools: gzip the file being served using a temporary file.
Devtools: gzip the file being served using a temporary file.

This avoids polluting the tree with .gz files when serving from the repo
root.

R=qsr@chromium.org

Review URL: https://codereview.chromium.org/1279543003 .

afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo,afandria/mojo