Record the last UMA system profile in prefs.

Also adds a function to read back the saved
system profile with corresponding tests. This
will be used by a following CL that splits
the UMA startup stability into a separate log.

BUG=312733
TEST=New unit tests.

Review URL: https://codereview.chromium.org/85373006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237796 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237796
Roll swarming_client @ aab3a62beb7e1d7a6785dcaee707479691fd6ddf.

The main difference with r237619 is the last commit that fixes a problem that
occured only on 32 bits python.

$ git log e98b112..aab3a62beb --date=short --format="%ad %ae %s" | sed 's/@chromium\.org//'
2013-11-28 maruel json.loads() may return a long value on 32 bits python.
2013-11-26 maruel Remove support of triggering multiple tasks at once in 'trigger'.
2013-11-22 maruel Stop making the tree read-only when 'read_only': True is not set.
2013-11-20 maruel Simplify imports, simplifying pylint checks.
2013-11-20 vadimsh@google.com Make stack traces produced by exceptions from TaskChannel.pull() more useful.
2013-11-19 maruel Create .isolated files via isolateserver.py archive <directory>.
2013-11-19 maruel Move more path handling code from isolate.py into utils/file_path.py.
2013-11-18 maruel Add ThreadProolWithProgress.iter_results() support.
2013-11-18 maruel Move code around in preparation to move code from isolate.py to isolateserver.py
2013-11-12 maruel In r192392, I +x'ed WATCHLISTS by accident. Fix that.
2013-11-12 maruel Partially revert 8732761d59. This broke executable bit.
2013-11-12 maruel Move read_json and write_json from trace_inputs to utils.tools.
2013-11-12 maruel Remove x bit on subprocess32.py, move auto_stub.py into third_party.
2013-11-11 maruel Rework swarming.py option grouping to be more sensible.
2013-11-11 maruel Enable setting the cache files as read-only.
2013-11-11 maruel Make file deletion more coherent with the behavior of each OSes.
2013-11-10 maruel Extract subprocess code into subprocess42.
2013-11-10 maruel Add test to confirm assumptions about file deletability across different OSes.
2013-11-08 maruel Exit the test sooner when it will fail anyway.
2013-11-08 maruel Preleminary work to make the file in the run_isolated.py cache read-only.
2013-11-08 maruel Fix run_test_case's Popen on Windows once and for all.
2013-11-06 maruel Remove support for file mode for symlink.
2013-11-06 maruel Fix trace_test_cases_smoke_test.py to stop leaking temp files.
2013-11-06 maruel Surface flags more so more settings can be configured at request time.
2013-11-06 maruel Remove slave_os as an hardcoded Manifest() dimension.
2013-11-06 maruel Make the environment completely configurable in the Manifest.

R=csharp@chromium.org
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/95173002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237797 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237798 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237798