[Telemetry] Fix application_energy_consumption output.

[Telemetry] Fix application_energy_consumption output.

Now we only try to calculate application_energy_consumption when we
actually have a known quiescent power draw. This means we'll still
output it on tab_switching, but not on page cycler. That should fix
errors like this:
http://build.chromium.org/p/chromium.perf/builders/Android%20Nexus5%20Perf/builds/2187/steps/page_cycler.morejs/logs/stdio

BUG=

Committed: https://crrev.com/6591b536018a42c402eadf5b7dc99eab7c0b8922
Cr-Commit-Position: refs/heads/master@{#299403}

[tonyg, 2014-10-13 23:23:50]

tonyg@chromium.org changed reviewers:
+ dtu@chromium.org, jeremy@chromium.org, sullivan@chromium.org

[dtu, 2014-10-13 23:27:50]

lgtm

[tonyg, 2014-10-13 23:29:04]

The CQ bit was checked by tonyg@chromium.org

[commit-bot: I haz the power, 2014-10-13 23:30:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/649903003/1

[commit-bot: I haz the power, 2014-10-14 00:25:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-14 00:26:11]

Patchset 1 (id:??) landed as
https://crrev.com/6591b536018a42c402eadf5b7dc99eab7c0b8922
Cr-Commit-Position: refs/heads/master@{#299403}