Second take at handling users with locally overridden diff-cmds.

Second take at handling users with locally overridden diff-cmds.

The first take at https://chromiumcodereview.appspot.com/14130006 tried to pass
"--diff-cmd diff", which doesn't work for e.g. Windows cmd users who don't have
a "diff" executable installed.

This take instead passes the "--internal-diff" switch which tells svn to ignore
any diff-cmd set locally and use its internal diff engine at all times.

While implementing this I found that the existing code tried to work around this
problem in a different way, by setting up a bogus config dir.  Since that
doesn't seem to work for me, and shouldn't be necessary with this patch anyway,
removed that code.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=194990

[M-A Ruel, 2013-04-18 19:58:11]

lgtm

[commit-bot: I haz the power, 2013-04-18 20:02:37]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkasting@chromium.org/14050007/1

[commit-bot: I haz the power, 2013-04-18 20:05:41]

Change committed as 194990

[Lei Zhang, 2013-04-18 21:31:57]

$ svn diff --internal-diff
svn: invalid option: --internal-diff                                            
                                                                                
                                                                                
                              
Type 'svn help' for usage.

$ svn --version                                                                 
                                                                                
                                                                
svn, version 1.6.17 (r1128011)                                                  
                                                                                
                                                                                
                                 compiled Dec 17 2011, 16:12:52

This is on Ubuntu Precise.

[iannucci, 2013-04-18 21:36:17]

On 2013/04/18 21:31:57, Lei Zhang wrote:
> $ svn diff --internal-diff
> svn: invalid option: --internal-diff                                          
 
>                                                                               
 
>                                                                               
 
>                               
> Type 'svn help' for usage.
> 
> $ svn --version                                                               
 
>                                                                               
 
>                                                                 
> svn, version 1.6.17 (r1128011)                                                
 
>                                                                               
 
>                                                                               
 
>                                  compiled Dec 17 2011, 16:12:52
> 
> This is on Ubuntu Precise.

Hate to be a downer, but this is blowing up CQ too:
https://codereview.chromium.org/14208016/

[Peter Kasting, 2013-04-18 21:37:07]

On 2013/04/18 21:31:57, Lei Zhang wrote:
> svn, version 1.6.17 (r1128011)                                                
 

Sigh.  Apparently --internal-diff is svn >= 1.7.  I assume supporting svn 1.6
and below is mandatory.

I guess I'll figure out a third take.

[Peter Kasting, 2013-04-18 21:39:05]

FYI, I reverted this in r195009.