This reverts commit 78624b68.

The reason is that install-build-deps.sh isn't meant to be run on mac
or windows, and this implementation ran it everywhere.

TBR=dpranke@chromium.org
BUG=229270

Review URL: https://codereview.chromium.org/1186893003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295686 0039d316-1c4b-4281-b951-d872f2087c98