Search for the source root rather than checkout root in clang_format.py.

Search for the source root rather than checkout root in clang_format.py.

Use the source root (src/ in Chromium) rather than the checkout root as
the path from which to locate the clang-format binaries.

webrtc uses the Chromium build/tools infrastructure but doesn't have
src/ as a source root path. This change allows us to continue to use
'git cl format' in a standalone webrtc checkout (which would be nice.)

BUG=240309
TESTED='git cl format' works on a trivial test change in both a
Chromium and webrtc checkout.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=248651

[ajm, 2014-01-28 01:54:31]

Interested to get your thoughts on this, Nick.

https://codereview.chromium.org/135653014/diff/40001/clang_format.py
File clang_format.py (right):

https://codereview.chromium.org/135653014/diff/40001/clang_format.py#newcode30
clang_format.py:30: source_root = gclient_utils.FindFileUpwards('.gn')
I at first wanted to use .clang-format here, but noticed that v8 has one as
well. This would break if run from under third_party/v8.

Open to alternatives.

[ajm, 2014-01-28 02:06:31]

Small update: this actually used to work in a standalone webrtc checkout, but
started to fail as of:
https://codereview.chromium.org/134313007

[ncarter (slow), 2014-01-30 00:35:05]

LGTM based on our email discussion -- I think this is the right way to go for
now (in that it fixes the symptoms), and I'll open a bug to discuss a more
structured way to integrate checkout-hosted tools with depot_tools commands.

https://codereview.chromium.org/135653014/diff/40001/clang_format.py
File clang_format.py (right):

https://codereview.chromium.org/135653014/diff/40001/clang_format.py#newcode30
clang_format.py:30: source_root = gclient_utils.FindFileUpwards('.gn')
On 2014/01/28 01:54:31, ajm wrote:
> I at first wanted to use .clang-format here, but noticed that v8 has one as
> well. This would break if run from under third_party/v8.
> 
> Open to alternatives.

I think .gn is the best of our currently available alternatives.

https://codereview.chromium.org/135653014/diff/40001/clang_format.py#newcode69
clang_format.py:69: # third_party/clang_format/bin.
oof, thanks for fixing these comments.

[ajm, 2014-01-30 01:22:37]

Thanks Nick.

Robbie, could you review for owner approval?

[iannucci, 2014-01-30 12:26:12]

lgtm with the stated caveats (i.e. this is all a hack and we need a real
mechanism for this)

[ajm, 2014-02-04 01:36:33]

On 2014/01/30 12:26:12, iannucci wrote:
> lgtm with the stated caveats (i.e. this is all a hack and we need a real
> mechanism for this)

Thanks and agreed.

[ajm, 2014-02-04 01:36:40]

The CQ bit was checked by ajm@chromium.org

[commit-bot: I haz the power, 2014-02-04 01:36:49]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ajm@chromium.org/135653014/60001

[commit-bot: I haz the power, 2014-02-04 01:38:37]

Change committed as 248651