Handle non-UTF-8 encoded files in presubmit checks.

Handle non-UTF-8 encoded files in presubmit checks.


BUG=
TEST=


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=146391

[chrisha, 2012-07-12 18:06:46]

This is an overly simplistic fix, but the issue is quite subtle.

Canned presubmit checks typically use _FindNewViolationsOfRule, which the uses
NewContents, which getst the contents via FileRead. The problem is that some
canned presubmit checks do not use a source-file filter, and this behaviour is
on purpose (for example, the DO NOT SUBMIT check). When binary files make it to
FileRead the whole thing blows up with a UTF-8 decoding error.

This is the simplest least invasive fix, but it hides the fact that a source
file may not be valid UTF-8.

Other options:

- Expose source file filters to the affected presubmit checks, and provide
appropriate defaults that don't check binary files.
- Use a file attribute aware FileRead function, and don't try to UTF-8 files
that are recognized as binary. (In all cases where this has bit me, git
correctly identified the file as having binary contents.)

So, consider this a stab in the dark as a fix. I'm willing to pursue the other
options if you think they are better.

[M-A Ruel, 2012-07-12 18:07:13]

lgtm

[commit-bot: I haz the power, 2012-07-12 18:07:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/chrisha@chromium.org/10696202/1

[commit-bot: I haz the power, 2012-07-12 18:10:29]

Change committed as 146391