docs: Change "ChromeOS" to "Chrome OS".

Correct a common typo/meme in the hopes of reducing its
spread.

BUG=none
TBR=brettw@chromium.org

Review-Url: https://codereview.chromium.org/2697323005
Cr-Original-Commit-Position: refs/heads/master@{#452121}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8171050893e6d8b3dd2814e89422e09eba952e4b
2 files changed
tree: 3f05a42e645a36469fffcb7245d0bc1939195395
  1. tools/