add browser benchmarking

- octane benchmarking imported under assets : do not review octane code.
  It should be kept as it is except one line change in index.html to print
  the final result to logcat.
  octane is from TOT of http://octane-benchmark.googlecode.com/svn/trunk/

- js code prints result to logcat using console.log API, and host side
  is capturing the result.

- browser is launched with web intent, so any default broswer can be used
  as long as console.log is redirected to logcat

- device is rebooted before each run as there is no way to force browser
  to refresh

Change-Id: I39a95a66bf6d2fc1ce1da915f182c3b542e642aa