Remove the ban on 'command' that are declared in included .isolate file.

Remove the ban on 'command' that are declared in included .isolate file.

Update the unit test to test the case where the command is overriden or not.

R=vadimsh@chromium.org
BUG=

Committed: https://code.google.com/p/swarming/source/detail?repo=client&r=f89de35

[M-A, 2013-12-13 20:58:40]

This is a problem when importing chrome.isolate from another other .isolate
since it defines a command. I think it's fine to define a command in
chrome.isolate and the other tests should simply override the command.

https://codereview.appspot.com/41950044/diff/1/tests/isolate_test.py
File tests/isolate_test.py (right):

https://codereview.appspot.com/41950044/diff/1/tests/isolate_test.py#newcode835
tests/isolate_test.py:835: # Falls back to isolate1 'command' and not
'isolate2'.
Right now, the first included take precedence. Actually, should it be the
reverse? I don't know.

[vadimsh, 2013-12-13 21:10:33]

https://codereview.appspot.com/41950044/diff/1/tests/isolate_test.py
File tests/isolate_test.py (right):

https://codereview.appspot.com/41950044/diff/1/tests/isolate_test.py#newcode835
tests/isolate_test.py:835: # Falls back to isolate1 'command' and not
'isolate2'.
On 2013/12/13 20:58:40, M-A wrote:
> Right now, the first included take precedence. Actually, should it be the
> reverse? I don't know.

I think reverse makes more sense. I think of it mentally as "second command
overrides first one".

[M-A, 2013-12-13 21:30:15]

https://codereview.appspot.com/41950044/diff/1/tests/isolate_test.py
File tests/isolate_test.py (right):

https://codereview.appspot.com/41950044/diff/1/tests/isolate_test.py#newcode835
tests/isolate_test.py:835: # Falls back to isolate1 'command' and not
'isolate2'.
On 2013/12/13 21:10:34, vadimsh wrote:
> On 2013/12/13 20:58:40, M-A wrote:
> > Right now, the first included take precedence. Actually, should it be the
> > reverse? I don't know.
> 
> I think reverse makes more sense. I think of it mentally as "second command
> overrides first one".

Done. I expanded the test a bit and added an error check too.

[vadimsh, 2013-12-13 21:43:48]

lgtm

[kbr1, 2013-12-13 22:00:17]

Thanks for implementing this! I had been pretty confused why the include didn't
work.

[M-A, 2013-12-13 22:06:54]

Committed patchset #3 manually as rf89de35 (presubmit successful).