Fix MB and running mash browser_tests under swarming

Fix MB and running browser_tests under mash

Unfortunately, the way to run a test on the bots can vary between
swarming and running directly; to run under swarming, you need
to ensure that the files needed to run the test and the command
line is embedded in the BUILD files (and gn_isolate_map) themselves,
rather than being able to specify them in the //testing/buildbot files.

This patch changes the way we were attempting to run tests
for mash on the chromium.mojo linux bot, so that the tests
are run under swarming.

In addition, this patch fixes a bunch of bugs uncovered when
trying to reproduce issues locally, and improves the help
documentation significantly.

R=sky@chromium.org
BUG=

Committed: https://crrev.com/030d7a6d83781190237c66c8f0317f24f356e428
Cr-Commit-Position: refs/heads/master@{#383457}

[Dirk Pranke, 2016-03-26 03:01:31]

Description was changed from

==========
Fix MB and running browser_tests under mash

R=sky@chromium.org
BUG=
==========

to

==========
Fix MB and running browser_tests under mash

Unfortunately, the way to run a test on the bots can vary between
swarming and running directly; to run under swarming, you need
to ensure that the files needed to run the test and the command 
line is embedded in the BUILD files (and gn_isolate_map) themselves,
rather than being able to specify them in the //testing/buildbot files.

This patch changes the way we were attempting to run tests
for mash on the chromium.mojo linux bot, so that the tests
are run under swarming.

In addition, this patch fixes a bunch of bugs uncovered when
trying to reproduce issues locally, and improves the help
documentation significantly.

R=sky@chromium.org
BUG=
==========

[Dirk Pranke, 2016-03-26 03:01:40]

Patchset #1 (id:1) has been deleted

[Dirk Pranke, 2016-03-26 03:02:41]

The CQ bit was checked by dpranke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-03-26 03:02:56]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1832093003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1832093003/20001

[commit-bot: I haz the power, 2016-03-26 04:19:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-03-26 04:19:37]

Dry run: This issue passed the CQ dry run.

[sky, 2016-03-26 15:17:48]

LGTM - thanks!

[Dirk Pranke, 2016-03-26 17:19:32]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2016-03-26 17:19:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1832093003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1832093003/20001

[commit-bot: I haz the power, 2016-03-26 17:24:02]

Description was changed from

==========
Fix MB and running browser_tests under mash

Unfortunately, the way to run a test on the bots can vary between
swarming and running directly; to run under swarming, you need
to ensure that the files needed to run the test and the command 
line is embedded in the BUILD files (and gn_isolate_map) themselves,
rather than being able to specify them in the //testing/buildbot files.

This patch changes the way we were attempting to run tests
for mash on the chromium.mojo linux bot, so that the tests
are run under swarming.

In addition, this patch fixes a bunch of bugs uncovered when
trying to reproduce issues locally, and improves the help
documentation significantly.

R=sky@chromium.org
BUG=
==========

to

==========
Fix MB and running browser_tests under mash

Unfortunately, the way to run a test on the bots can vary between
swarming and running directly; to run under swarming, you need
to ensure that the files needed to run the test and the command 
line is embedded in the BUILD files (and gn_isolate_map) themselves,
rather than being able to specify them in the //testing/buildbot files.

This patch changes the way we were attempting to run tests
for mash on the chromium.mojo linux bot, so that the tests
are run under swarming.

In addition, this patch fixes a bunch of bugs uncovered when
trying to reproduce issues locally, and improves the help
documentation significantly.

R=sky@chromium.org
BUG=
==========

[commit-bot: I haz the power, 2016-03-26 17:24:04]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-03-26 17:25:22]

Description was changed from

==========
Fix MB and running browser_tests under mash

Unfortunately, the way to run a test on the bots can vary between
swarming and running directly; to run under swarming, you need
to ensure that the files needed to run the test and the command 
line is embedded in the BUILD files (and gn_isolate_map) themselves,
rather than being able to specify them in the //testing/buildbot files.

This patch changes the way we were attempting to run tests
for mash on the chromium.mojo linux bot, so that the tests
are run under swarming.

In addition, this patch fixes a bunch of bugs uncovered when
trying to reproduce issues locally, and improves the help
documentation significantly.

R=sky@chromium.org
BUG=
==========

to

==========
Fix MB and running browser_tests under mash

Unfortunately, the way to run a test on the bots can vary between
swarming and running directly; to run under swarming, you need
to ensure that the files needed to run the test and the command
line is embedded in the BUILD files (and gn_isolate_map) themselves,
rather than being able to specify them in the //testing/buildbot files.

This patch changes the way we were attempting to run tests
for mash on the chromium.mojo linux bot, so that the tests
are run under swarming.

In addition, this patch fixes a bunch of bugs uncovered when
trying to reproduce issues locally, and improves the help
documentation significantly.

R=sky@chromium.org
BUG=

Committed: https://crrev.com/030d7a6d83781190237c66c8f0317f24f356e428
Cr-Commit-Position: refs/heads/master@{#383457}
==========

[commit-bot: I haz the power, 2016-03-26 17:25:23]

Patchset 1 (id:??) landed as
https://crrev.com/030d7a6d83781190237c66c8f0317f24f356e428
Cr-Commit-Position: refs/heads/master@{#383457}