Remove tracing's nesting logic since noone is using it.

Remove tracing's nesting logic since noone is using it.

Cleanup tracing_backend_unittest

BUG=400859
Committed: https://crrev.com/18cd46f23e277773ffa3b0ef2715d849999d76c7
Cr-Commit-Position: refs/heads/master@{#298310}

[nednguyen, 2014-09-10 23:13:49]

nednguyen@google.com changed reviewers:
+ nduca@chromium.org, tonyg@chromium.org

[tonyg, 2014-09-10 23:29:18]

tonyg@chromium.org changed reviewers:
+ dtu@chromium.org
- tonyg@chromium.org

[tonyg, 2014-09-10 23:29:38]

tonyg@chromium.org changed reviewers:
+ tonyg@chromium.org

[tonyg, 2014-09-10 23:29:39]

I don't know this part too well. Dave, would you mind taking a look please?

[nduca, 2014-09-11 00:09:07]

lgtm on my part as long as dtu is happy

[nednguyen, 2014-09-11 22:32:16]

nednguyen@google.com changed reviewers:
+ chrishenry@google.com

[dtu, 2014-09-15 22:06:33]

lol thanks guys, I'm also unfamiliar with this code

https://chromiumcodereview.appspot.com/561053002/diff/20001/tools/telemetry/t...
File tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py (right):

https://chromiumcodereview.appspot.com/561053002/diff/20001/tools/telemetry/t...
tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py:41: if
self.is_tracing_running:
Maybe we don't need this check and/or this variable?
If we remove this we can also remove _category_filter?

[nednguyen, 2014-09-15 22:09:48]

https://chromiumcodereview.appspot.com/561053002/diff/20001/tools/telemetry/t...
File tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py (right):

https://chromiumcodereview.appspot.com/561053002/diff/20001/tools/telemetry/t...
tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py:41: if
self.is_tracing_running:
On 2014/09/15 22:06:33, dtu wrote:
> Maybe we don't need this check and/or this variable?
> If we remove this we can also remove _category_filter?

No, if we allow StartTracing to be called multiple times. Or else, this need to
raise Exception to let caller knows that tracing is already running.

[chrishenry, 2014-09-23 17:49:27]

https://codereview.chromium.org/561053002/diff/20001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py (right):

https://codereview.chromium.org/561053002/diff/20001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py:41: if
self.is_tracing_running:
On 2014/09/15 22:09:47, nednguyen wrote:
> On 2014/09/15 22:06:33, dtu wrote:
> > Maybe we don't need this check and/or this variable?
> > If we remove this we can also remove _category_filter?
> 
> No, if we allow StartTracing to be called multiple times. Or else, this need
to
> raise Exception to let caller knows that tracing is already running.

Should we throw exception? The return value from StopTracing is a bit weird if
it's nested.

[nednguyen, 2014-10-03 17:13:48]

PTAL

https://codereview.chromium.org/561053002/diff/20001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py (right):

https://codereview.chromium.org/561053002/diff/20001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py:41: if
self.is_tracing_running:
On 2014/09/23 17:49:26, chrishenry wrote:
> On 2014/09/15 22:09:47, nednguyen wrote:
> > On 2014/09/15 22:06:33, dtu wrote:
> > > Maybe we don't need this check and/or this variable?
> > > If we remove this we can also remove _category_filter?
> > 
> > No, if we allow StartTracing to be called multiple times. Or else, this need
> to
> > raise Exception to let caller knows that tracing is already running.
> 
> Should we throw exception? The return value from StopTracing is a bit weird if
> it's nested.

tracing_controller_backend return False in case it's started. Let's make it
consistent.

https://codereview.chromium.org/561053002/diff/20001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/backends/chrome/tracing_backend.py:41: if
self.is_tracing_running:
On 2014/09/15 22:06:33, dtu wrote:
> Maybe we don't need this check and/or this variable?
> If we remove this we can also remove _category_filter?

done.

[dtu, 2014-10-06 23:18:45]

The CQ bit was checked by dtu@chromium.org

[dtu, 2014-10-06 23:18:45]

lgtm

[commit-bot: I haz the power, 2014-10-06 23:20:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/561053002/40001

[commit-bot: I haz the power, 2014-10-07 00:04:17]

Committed patchset #3 (id:40001) as 7b3d9e63d65f1626e604daf048252d269894da8c

[commit-bot: I haz the power, 2014-10-07 00:04:54]

Patchset 3 (id:??) landed as
https://crrev.com/18cd46f23e277773ffa3b0ef2715d849999d76c7
Cr-Commit-Position: refs/heads/master@{#298310}