DevTools: Remove 20kb of unused CSS

These css rules used classes that don't exist anywhere in the
javascript. A script was written to find them, but manually checking
is still needed because some scripts generate class names by
string concatenation like 'icon-' + iconType

Change-Id: I15c4f26451b9fa371b366a8977021e2af7eca449
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1618043
Commit-Queue: Joel Einbinder <einbinder@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Reviewed-by: Erik Luo <luoe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661630}
43 files changed