Cleanup: Merge a bunch of redundent env['GIT_PAGER'] = 'cat' statements.

Cleanup: Merge a bunch of redundent env['GIT_PAGER'] = 'cat' statements.

Additionally:
- replace some RunCommand(['git', ...]) calls with RunGit().
- replace Settings._GetConfig('rietveld.foo') _GetRietveldConfig('foo').
- merge and cache calls to git rev-parse --show-cdup.
- merge some calls to git merge-base.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=250248

[Lei Zhang, 2014-02-08 07:11:35]

More magical cats, less lines of code.

[iannucci, 2014-02-08 21:19:45]

On 2014/02/08 07:11:35, Lei Zhang wrote:
> More magical cats, less lines of code.

Hm... as much as I hate environment variables, why not just set
`os.environ['GIT_PAGER'] = 'cat'` in main()?

If there really are code paths which need to preserve it (I don't think there
are?), we could even save the old value off to a module-level variable, and then
when preparing env's add it back in...

[M-A Ruel, 2014-02-10 15:23:45]

I'll let Robbie do the finally review but just keep in mind some of the code in
there was there to support git 1.5.x. So some of the hacks are likely not
necessary anymore, I'm fine with dropping support for anything below git 1.7.

[Lei Zhang, 2014-02-10 19:57:19]

On 2014/02/08 21:19:45, iannucci wrote:
> On 2014/02/08 07:11:35, Lei Zhang wrote:
> > More magical cats, less lines of code.
> 
> Hm... as much as I hate environment variables, why not just set
> `os.environ['GIT_PAGER'] = 'cat'` in main()?
> 
> If there really are code paths which need to preserve it (I don't think there
> are?), we could even save the old value off to a module-level variable, and
then
> when preparing env's add it back in...

I don't know if any code path really needs it. I'm just refactoring the existing
code. I'll put it in main() and ping you when I upload patch set 3.

[Lei Zhang, 2014-02-10 23:53:41]

On 2014/02/08 21:19:45, iannucci wrote:
> On 2014/02/08 07:11:35, Lei Zhang wrote:
> > More magical cats, less lines of code.
> 
> Hm... as much as I hate environment variables, why not just set
> `os.environ['GIT_PAGER'] = 'cat'` in main()?
> 
> If there really are code paths which need to preserve it (I don't think there
> are?), we could even save the old value off to a module-level variable, and
then
> when preparing env's add it back in...

Actually, I see a couple "import git_cl" statements from within depot_tools. If
others are reusing this code, then setting it once in main() is not sufficient.

[iannucci, 2014-02-11 00:12:41]

On 2014/02/10 23:53:41, Lei Zhang wrote:
> On 2014/02/08 21:19:45, iannucci wrote:
> > On 2014/02/08 07:11:35, Lei Zhang wrote:
> > > More magical cats, less lines of code.
> > 
> > Hm... as much as I hate environment variables, why not just set
> > `os.environ['GIT_PAGER'] = 'cat'` in main()?
> > 
> > If there really are code paths which need to preserve it (I don't think
there
> > are?), we could even save the old value off to a module-level variable, and
> then
> > when preparing env's add it back in...
> 
> Actually, I see a couple "import git_cl" statements from within depot_tools.
If
> others are reusing this code, then setting it once in main() is not
sufficient.

barf :(.

Ok, fine, lgtm.

[Lei Zhang, 2014-02-11 00:31:45]

The CQ bit was checked by thestig@chromium.org

[commit-bot: I haz the power, 2014-02-11 00:31:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thestig@chromium.org/157913005/30001

[commit-bot: I haz the power, 2014-02-11 00:33:38]

Change committed as 250248