Add MB commands for generating isolates and running them.

Add MB commands for generating isolates and running them.

Since the logic for handling isolates in GN is split between
the GN and MB tools, it's harder to build and test isolates
with GN than it is with GYP (where you can just say 'ninja base_unittests_run'
to build the isolate).

This patch adds two new commands to the MB tool to make things easier.

The first is `mb isolate`, which is the equivalent of the
GYP _run targets: it creates the .isolate and .isolated.gen.json files.

The second is `mb run`, which is a convenient wrapper command that
runs mb isolate, runs ninja to ensure that the test is actually built
and up-to-date, and then runs the swarming_client commands to actually
run the test locally (in an isolated directory).

Both commands will work either off of an existing build directory or
in a new directory (if given the -m/-b or -c flags).

R=kbr@chromium.org
BUG=

Committed: https://crrev.com/751516abefd8b10853c103c563345b5e04de970d
Cr-Commit-Position: refs/heads/master@{#352217}

[Dirk Pranke, 2015-09-29 02:28:09]

dpranke@chromium.org changed reviewers:
+ kbr@chromium.org

[Dirk Pranke, 2015-09-29 02:28:36]

Ken, FYI ...

This isn't quite ready for review and landing yet, as I want to add some unit
tests, but it's functional and at least close.

[Ken Russell (switch to Gerrit), 2015-09-29 06:55:45]

Thanks for adding these commands. They'll be very helpful.

It's unfortunate that the mb fix in Ned's patch
https://codereview.chromium.org/1354223004/ hasn't landed yet, but it looks like
it won't conflict with these new commands.

[nednguyen, 2015-09-29 15:38:33]

On 2015/09/29 06:55:45, Ken Russell wrote:
> Thanks for adding these commands. They'll be very helpful.
> 
> It's unfortunate that the mb fix in Ned's patch
> https://codereview.chromium.org/1354223004/ hasn't landed yet, but it looks
like
> it won't conflict with these new commands.

I am splitting the mb fix to a different patch & try to land it.

[Dirk Pranke, 2015-10-02 01:58:31]

Patchset #3 (id:40001) has been deleted

[Dirk Pranke, 2015-10-02 02:02:53]

Okay, I think this is ready for review. 

I should still add some unittests for this, but the existing tests cover the
changed functionality, so it's only the new commands that are still untested,
and they're somewhat less important since nothing uses them yet and they'll only
be used by users for now, not bots, so it's not the end of the world if they're
broken.

Hopefully I'll have time to write some tests tomorrow, but I'd rather get this
landed sooner rather than later and I don't want to hold this up too long. If
you'd rather wait until I add tests, that's fine, too.

[Ken Russell (switch to Gerrit), 2015-10-02 18:08:20]

LGTM to land before unit tests. The important thing is that the commands work.

https://codereview.chromium.org/1370373005/diff/60001/tools/mb/mb.py
File tools/mb/mb.py (right):

https://codereview.chromium.org/1370373005/diff/60001/tools/mb/mb.py#newcode211
tools/mb/mb.py:211: self.ToSrcRelPath('%s/%s.isolated' % (build_dir, target))])
Will this '/' cause problems on Windows? I'm guessing not but wanted to check.
Same question throughout.

[Dirk Pranke, 2015-10-02 18:29:37]

On 2015/10/02 18:08:20, Ken Russell wrote:
> LGTM to land before unit tests. The important thing is that the commands work.
> 
> https://codereview.chromium.org/1370373005/diff/60001/tools/mb/mb.py
> File tools/mb/mb.py (right):
> 
>
https://codereview.chromium.org/1370373005/diff/60001/tools/mb/mb.py#newcode211
> tools/mb/mb.py:211: self.ToSrcRelPath('%s/%s.isolated' % (build_dir,
target))])
> Will this '/' cause problems on Windows? I'm guessing not but wanted to check.
> Same question throughout.

Good question. ToSrcRelPath() expects unix-style forward slashes and converts 
'/' to os.sep, so it'll do the right thing.

[Dirk Pranke, 2015-10-02 23:18:27]

added some basic unit tests and fixed some bugs.

[Dirk Pranke, 2015-10-02 23:18:32]

The CQ bit was checked by dpranke@chromium.org

[Dirk Pranke, 2015-10-02 23:18:33]

The patchset sent to the CQ was uploaded after l-g-t-m from kbr@chromium.org
Link to the patchset: https://codereview.chromium.org/1370373005/#ps80001
(title: "add some basic unit tests for coverage of isolate and run")

[commit-bot: I haz the power, 2015-10-02 23:20:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1370373005/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1370373005/80001

[commit-bot: I haz the power, 2015-10-03 01:11:47]

Committed patchset #4 (id:80001)

[commit-bot: I haz the power, 2015-10-03 01:12:36]

Patchset 4 (id:??) landed as
https://crrev.com/751516abefd8b10853c103c563345b5e04de970d
Cr-Commit-Position: refs/heads/master@{#352217}