Allow for lists of lists when summarizing performance results

Allow for lists of lists when summarizing performance results

Using page-repeat and pageset-repeat options in commands like
tools/perf/run_measurement --browser=release --page-repeat=2 --pageset-repeat=3 blink_perf third_party/WebKit/PerformanceTests/Parser/html-parser.html
previously let to a crash in _MeanAndStdDevFromList.

BUG=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=207426

[bulach, 2013-06-19 12:19:42]

lgtm, thanks! some style nits below.

https://codereview.chromium.org/17390017/diff/1/build/android/pylib/perf_test...
File build/android/pylib/perf_tests_helper.py (right):

https://codereview.chromium.org/17390017/diff/1/build/android/pylib/perf_test...
build/android/pylib/perf_tests_helper.py:24: 
nit: add another \n here and after the function (i.e., styleguide says two \n
between top-levels)

https://codereview.chromium.org/17390017/diff/1/build/android/pylib/perf_test...
build/android/pylib/perf_tests_helper.py:26: """Returns a simple list without
sub-lists."""
nit: indentation should be 2 rather than 4

https://codereview.chromium.org/17390017/diff/1/build/android/pylib/perf_test...
build/android/pylib/perf_tests_helper.py:94: values: A list of numeric measured
values.
nit: probably best to expand this, something like "N-dimensional lists will be
flattened and treated as a simple list".

[commit-bot: I haz the power, 2013-06-20 01:55:04]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ericwilligers@chromium.org/17390017/6001

[commit-bot: I haz the power, 2013-06-20 14:02:42]

Change committed as 207426