Instrumenting callback of DiskCacheBasedQuicServerInfo::OnIOComplete

Instrumenting callback of DiskCacheBasedQuicServerInfo::OnIOComplete.

Latest instrumentations show that most of jank comes from DiskCacheBasedQuicServerInfo::OnIOComplete (17.1). Note that it calls DiskCacheBasedQuicServerInfo::DoLoop, which calls a bunch of methods, all of them instrumented now. The above jank happens outside of the DoLoop call, and outside of DiskCacheBasedQuicServerInfo::PersistInternal call.

This points to wait_for_ready_callback_ callback. Instrumenting more.

(There is also 3.4 jank in Transaction::OnIOComplete, but this is not my focus now.)

BUG=422516
Committed: https://crrev.com/e12cac8a794e5f2d34d0253981407c841d44443c
Cr-Commit-Position: refs/heads/master@{#307966}

[vadimt, 2014-12-09 00:48:11]

vadimt@chromium.org changed reviewers:
+ gavinp@chromium.org

[vadimt, 2014-12-09 00:48:12]

gavinp@, please review

[mmenke, 2014-12-11 17:59:09]

LGTM, rubberstamp

[vadimt, 2014-12-11 18:36:39]

The CQ bit was checked by vadimt@chromium.org

[commit-bot: I haz the power, 2014-12-11 18:37:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/789483004/1

[commit-bot: I haz the power, 2014-12-11 18:42:39]

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

[commit-bot: I haz the power, 2014-12-11 18:42:40]

Try jobs failed on following builders:
  linux_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/linux_gpu/builds/...)
  android_chromium_gn_compile_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)
  linux_chromium_asan_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_gn_dbg on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_gn_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_rel_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  ios_rel_device_ninja on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)
  mac_chromium_compile_dbg_ng on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  win_chromium_compile_dbg on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)
  win_chromium_rel_ng on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)
  win_chromium_x64_rel_ng on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[vadimt, 2014-12-11 19:03:20]

The CQ bit was checked by vadimt@chromium.org

[commit-bot: I haz the power, 2014-12-11 19:04:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/789483004/20001

[commit-bot: I haz the power, 2014-12-11 20:46:54]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-12-11 20:47:40]

Patchset 2 (id:??) landed as
https://crrev.com/e12cac8a794e5f2d34d0253981407c841d44443c
Cr-Commit-Position: refs/heads/master@{#307966}