Add .gitignore file
Add .gitignore file

R=brettw@chromium.org
BUG=

Review URL: https://codereview.chromium.org/302633005

azunite/chrome_buildtools,SuYiling/chrome_buildtools,SuYiling/chrome_buildtools,SuYiling/chrome_buildtools,azunite/chrome_buildtools,azunite/chrome_buildtools