Add Don't end with whitespaces and <=80 cols rules.

- Add «no trailing whitespace» and <=80 cols rules.
- Remove the invalid import os statement (PRESUBMIT.py shouldn't import anything).
- Add excluded paths. Mostly third parties.
- Increase what is considered a source file.
- Don't check for DO NOT SUBMIT on upload.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=10983

[Nicolas Sylvain, 2009-02-26 21:51:33]

The code looks ok, but this is just going to be too annoying.

We have hundreds of file in the repo with tabs, spaces at the end of lines and
stuff like that. We can't force everyone to care about the style nits of other
people just because they want to modify the file.

All the things that you check have something in common, they can be easily be
put in a script and can be fixed automatically. You could run it once a day,
check the diff, and if it makes sense, you submit. Then we'll be sure that the
tree does not contain any of these things, and we can enable this code in the
presubmit code.... 

But again... there is nothing better than asking reviewers to look at the style
and lint errors.

http://codereview.chromium.org/28219/diff/1/2
File PRESUBMIT.py (right):

http://codereview.chromium.org/28219/diff/1/2#newcode82
Line 82: '%s, line %s, %s chars' %
more verbose please. "Line over 80char. Len=X"