Revert of [chromeos/about:power] Collect cpuidle and cpufreq stats (https://codereview.chromium.org/149973002/)

Reason for revert:
Per Sadrul's comment, this causes a crash several seconds after startup.

Original issue's description:
> [chromeos/about:power] Collect and display cpuidle and cpufreq stats
>   
> Salient changes introduced by this CL:
> 1. PowerDataCollector collects CPU idle and CPU freq state
>    information.
> 2. The about:power page is organized into expandable 
>    sections.
> 3. Two sections, "Idle State Data" and "Frequency State 
>    Data" are added to the page.
> 4. Plots have a legend.
> 
> BUG=335816
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=256294

TBR=snanda@chromium.org,arv@chromium.org,sivachandra@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=335816

Review URL: https://codereview.chromium.org/196613002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256410 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256410