[Telemetry] Improve Android cycle time.

[Telemetry] Improve Android cycle time.

There's no need to eagerly install the file_poller. This ensure we only do it
when we're running a measurement that needs it.

BUG=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272575

[qsr, 2014-05-23 09:15:36]

https://codereview.chromium.org/298873006/diff/1/tools/telemetry/telemetry/co...
File
tools/telemetry/telemetry/core/platform/power_monitor/android_ds2784_power_monitor.py
(right):

https://codereview.chromium.org/298873006/diff/1/tools/telemetry/telemetry/co...
tools/telemetry/telemetry/core/platform/power_monitor/android_ds2784_power_monitor.py:46:
self._device, 'file_poller')
Do you want to cache that you did that already once? As otherwise it will be
called between each page of a test suite, or is the second call mostly free?

[tonyg, 2014-05-23 13:33:17]

https://codereview.chromium.org/298873006/diff/1/tools/telemetry/telemetry/co...
File
tools/telemetry/telemetry/core/platform/power_monitor/android_ds2784_power_monitor.py
(right):

https://codereview.chromium.org/298873006/diff/1/tools/telemetry/telemetry/co...
tools/telemetry/telemetry/core/platform/power_monitor/android_ds2784_power_monitor.py:46:
self._device, 'file_poller')
On 2014/05/23 09:15:36, qsr wrote:
> Do you want to cache that you did that already once? As otherwise it will be
> called between each page of a test suite, or is the second call mostly free?

InstallOnDevice has @decorators.Cache. So the subsequent calls are free.

[qsr, 2014-05-23 13:45:17]

lgtm

[tonyg, 2014-05-23 13:48:45]

The CQ bit was checked by tonyg@chromium.org

[commit-bot: I haz the power, 2014-05-23 13:48:59]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tonyg@chromium.org/298873006/1

[commit-bot: I haz the power, 2014-05-23 16:03:27]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  mac_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu_triggered...)

[commit-bot: I haz the power, 2014-05-23 16:05:42]

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

[commit-bot: I haz the power, 2014-05-23 16:05:43]

Try jobs failed on following builders:
  mac_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu_triggered...)

[tonyg, 2014-05-23 16:48:59]

The CQ bit was checked by tonyg@chromium.org

[commit-bot: I haz the power, 2014-05-23 16:50:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tonyg@chromium.org/298873006/1

[commit-bot: I haz the power, 2014-05-23 19:03:33]

Change committed as 272575