cc: Abstract out proxy timing history

cc: Abstract out proxy timing history

Pulling this out into a separate class lets it be reused by SingleThreadProxy.

BUG=329552
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251471

[enne (OOO), 2014-02-13 01:12:48]

Here's something I'll need to do for https://codereview.chromium.org/134623005/,
but seemed like I could break it off into this smaller patch.

[brianderson, 2014-02-13 01:29:54]

lgtm

+ajuma for fyi.

[enne (OOO), 2014-02-13 01:33:13]

The CQ bit was checked by enne@chromium.org

[commit-bot: I haz the power, 2014-02-13 01:37:47]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/154163005/50001

[commit-bot: I haz the power, 2014-02-13 02:22:01]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-13 02:22:02]

Retried try job too often on win_rel for step(s) app_list_unittests,
ash_unittests, aura_unittests, base_unittests, browser_tests,
cacheinvalidation_unittests, cc_unittests, check_deps, check_deps2git,
chrome_elf_unittests, chromedriver_unittests, components_unittests,
compositor_unittests, content_browsertests, content_unittests, crypto_unittests,
events_unittests, google_apis_unittests, gpu_unittests,
installer_util_unittests, interactive_ui_tests, ipc_tests, jingle_unittests,
media_unittests, mini_installer_test, nacl_integration, net_unittests,
ppapi_unittests, printing_unittests, remoting_unittests, sql_unittests,
sync_integration_tests, sync_unit_tests, telemetry_perf_unittests,
telemetry_unittests, unit_tests, views_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[enne (OOO), 2014-02-14 21:52:15]

The CQ bit was checked by enne@chromium.org

[commit-bot: I haz the power, 2014-02-14 21:57:30]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/154163005/50001

[commit-bot: I haz the power, 2014-02-15 01:11:55]

Change committed as 251471