Make sure files end with exactly one new line and police this in presubmit.

Make sure files end with exactly one new line and police this in presubmit.

The changes are (excluding presubmit.py) mechanical. I added the following
lines after the check and iterated the presubmit script until all errors
went away:

f = open(name, "w");
if contents.endswith('\n\n'):
  f.write(contents[0:-1])
else:
  f.write(contents + '\n')

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/82803005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18017 ce2b1a6d-e550-0410-aec6-3dcde31c8c00