telemetry: Add rasterize_and_record benchmark for silk pages

Add a rasterize_and_record benchmark for the silk page set so that we can track
improvements.

BUG=304298

Review URL: https://codereview.chromium.org/80643003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236526 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236526