pyauto perf: Instrument YoutubeCPU test so we get more data to analyze behavior. Also fix an integer conversion issue.
pyauto perf: Instrument YoutubeCPU test so we get more data to
analyze behavior. Also fix an integer conversion issue.

BUG=chromium-os:25456
TEST=ran on my Z600

Review URL: http://codereview.chromium.org/9325013

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@120544 0039d316-1c4b-4281-b951-d872f2087c98

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